diff --git a/Cargo.lock b/Cargo.lock
index 06f8b51f0a..30965c8b64 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -540,7 +540,7 @@ dependencies = [
  "alloy-rlp",
  "alloy-serde",
  "alloy-sol-types",
- "itertools 0.13.0",
+ "itertools 0.14.0",
  "serde",
  "serde_json",
  "serde_with",
@@ -674,7 +674,7 @@ checksum = "ae9abaedb9123ebe4b1527bc88a0409d65b2727c3de89a289284ba91ad70ae99"
 dependencies = [
  "alloy-json-rpc",
  "alloy-transport",
- "itertools 0.13.0",
+ "itertools 0.14.0",
  "reqwest 0.13.2",
  "serde_json",
  "tower",
@@ -3507,7 +3507,7 @@ dependencies = [
  "dyn-clone",
  "foundry-compilers-artifacts",
  "foundry-compilers-core",
- "itertools 0.13.0",
+ "itertools 0.14.0",
  "path-slash",
  "rayon",
  "semver 1.0.27",
@@ -9615,7 +9615,7 @@ dependencies = [
  "derive_more 2.1.1",
  "dunce",
  "inturn",
- "itertools 0.11.0",
+ "itertools 0.14.0",
  "itoa",
  "normalize-path",
  "once_map",
@@ -9651,7 +9651,7 @@ dependencies = [
  "alloy-primitives",
  "bitflags",
  "bumpalo",
- "itertools 0.11.0",
+ "itertools 0.14.0",
  "memchr",
  "num-bigint 0.4.6",
  "num-rational",
diff --git a/benchmarks/guest/base64_json/src/main.rs b/benchmarks/guest/base64_json/src/main.rs
index 3adf07be60..9b28003202 100644
--- a/benchmarks/guest/base64_json/src/main.rs
+++ b/benchmarks/guest/base64_json/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/bincode/src/main.rs b/benchmarks/guest/bincode/src/main.rs
index 0a5f3e252c..306e9b57ba 100644
--- a/benchmarks/guest/bincode/src/main.rs
+++ b/benchmarks/guest/bincode/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/bubblesort/src/main.rs b/benchmarks/guest/bubblesort/src/main.rs
index ccbe1db7e0..3581422e95 100644
--- a/benchmarks/guest/bubblesort/src/main.rs
+++ b/benchmarks/guest/bubblesort/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/benchmarks/guest/ecrecover/src/main.rs b/benchmarks/guest/ecrecover/src/main.rs
index 2028f26a38..75222975d7 100644
--- a/benchmarks/guest/ecrecover/src/main.rs
+++ b/benchmarks/guest/ecrecover/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/fibonacci/src/main.rs b/benchmarks/guest/fibonacci/src/main.rs
index b907f1a705..37006d6789 100644
--- a/benchmarks/guest/fibonacci/src/main.rs
+++ b/benchmarks/guest/fibonacci/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::{read, reveal_u64};
diff --git a/benchmarks/guest/fibonacci_iterative/src/main.rs b/benchmarks/guest/fibonacci_iterative/src/main.rs
index d25c83abb7..636d916053 100644
--- a/benchmarks/guest/fibonacci_iterative/src/main.rs
+++ b/benchmarks/guest/fibonacci_iterative/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/fibonacci_recursive/src/main.rs b/benchmarks/guest/fibonacci_recursive/src/main.rs
index 5bfffb20ed..e50c74e689 100644
--- a/benchmarks/guest/fibonacci_recursive/src/main.rs
+++ b/benchmarks/guest/fibonacci_recursive/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/keccak256/src/main.rs b/benchmarks/guest/keccak256/src/main.rs
index 0bb07be5d7..16bb17e0a4 100644
--- a/benchmarks/guest/keccak256/src/main.rs
+++ b/benchmarks/guest/keccak256/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/benchmarks/guest/keccak256_iter/src/main.rs b/benchmarks/guest/keccak256_iter/src/main.rs
index f17ad699a9..b7a73d7b91 100644
--- a/benchmarks/guest/keccak256_iter/src/main.rs
+++ b/benchmarks/guest/keccak256_iter/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/benchmarks/guest/kitchen-sink/src/main.rs b/benchmarks/guest/kitchen-sink/src/main.rs
index c76050343c..fd8a016d66 100644
--- a/benchmarks/guest/kitchen-sink/src/main.rs
+++ b/benchmarks/guest/kitchen-sink/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/pairing/src/main.rs b/benchmarks/guest/pairing/src/main.rs
index 438a2e4c65..5e3ee44e11 100644
--- a/benchmarks/guest/pairing/src/main.rs
+++ b/benchmarks/guest/pairing/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/benchmarks/guest/quicksort/src/main.rs b/benchmarks/guest/quicksort/src/main.rs
index 363dfd1f14..a5a87487c0 100644
--- a/benchmarks/guest/quicksort/src/main.rs
+++ b/benchmarks/guest/quicksort/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/benchmarks/guest/regex/src/main.rs b/benchmarks/guest/regex/src/main.rs
index c469dcd51f..8081472c30 100644
--- a/benchmarks/guest/regex/src/main.rs
+++ b/benchmarks/guest/regex/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/revm_snailtracer/src/main.rs b/benchmarks/guest/revm_snailtracer/src/main.rs
index a98f699ac3..b91edfcb5e 100644
--- a/benchmarks/guest/revm_snailtracer/src/main.rs
+++ b/benchmarks/guest/revm_snailtracer/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/revm_transfer/src/main.rs b/benchmarks/guest/revm_transfer/src/main.rs
index 9a69405ea2..3c251505db 100644
--- a/benchmarks/guest/revm_transfer/src/main.rs
+++ b/benchmarks/guest/revm_transfer/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 //! Program to match the workload of <https://github.com/bluealloy/revm/blob/900409f134c1cbd4489d370a6b037f354afa4a5c/crates/revm/benches/bench.rs#L68>
diff --git a/benchmarks/guest/rkyv/src/main.rs b/benchmarks/guest/rkyv/src/main.rs
index 0f11cedb6a..83acb2c8b7 100644
--- a/benchmarks/guest/rkyv/src/main.rs
+++ b/benchmarks/guest/rkyv/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/sha256/src/main.rs b/benchmarks/guest/sha256/src/main.rs
index c4c261e4df..5c58cc9305 100644
--- a/benchmarks/guest/sha256/src/main.rs
+++ b/benchmarks/guest/sha256/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/benchmarks/guest/sha256_iter/src/main.rs b/benchmarks/guest/sha256_iter/src/main.rs
index f09ca65cb8..75aa431d73 100644
--- a/benchmarks/guest/sha256_iter/src/main.rs
+++ b/benchmarks/guest/sha256_iter/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/benchmarks/guest/sha2_bench/src/main.rs b/benchmarks/guest/sha2_bench/src/main.rs
index 42b28edb16..ce896fe96a 100644
--- a/benchmarks/guest/sha2_bench/src/main.rs
+++ b/benchmarks/guest/sha2_bench/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/crates/cli/templates/main.rs b/crates/cli/templates/main.rs
index 2f3590bd4d..da6af3522e 100644
--- a/crates/cli/templates/main.rs
+++ b/crates/cli/templates/main.rs
@@ -1,5 +1,5 @@
 // src/main.rs
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::{read, reveal_u64};
diff --git a/crates/cli/tests/programs/fibonacci/src/main.rs b/crates/cli/tests/programs/fibonacci/src/main.rs
index 762644c694..31ef048195 100644
--- a/crates/cli/tests/programs/fibonacci/src/main.rs
+++ b/crates/cli/tests/programs/fibonacci/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/crates/cli/tests/programs/multi/calculator/examples/fibonacci.rs b/crates/cli/tests/programs/multi/calculator/examples/fibonacci.rs
index e66d0c91f3..b14ed5458c 100644
--- a/crates/cli/tests/programs/multi/calculator/examples/fibonacci.rs
+++ b/crates/cli/tests/programs/multi/calculator/examples/fibonacci.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/crates/cli/tests/programs/multi/calculator/src/main.rs b/crates/cli/tests/programs/multi/calculator/src/main.rs
index 3545517b3f..5317839422 100644
--- a/crates/cli/tests/programs/multi/calculator/src/main.rs
+++ b/crates/cli/tests/programs/multi/calculator/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use calculator::count_primes;
diff --git a/crates/cli/tests/programs/multi/string-utils/examples/palindrome.rs b/crates/cli/tests/programs/multi/string-utils/examples/palindrome.rs
index 9ebcff8da2..c678cf8fe1 100644
--- a/crates/cli/tests/programs/multi/string-utils/examples/palindrome.rs
+++ b/crates/cli/tests/programs/multi/string-utils/examples/palindrome.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/crates/cli/tests/programs/multi/string-utils/src/main.rs b/crates/cli/tests/programs/multi/string-utils/src/main.rs
index f868d98fd5..b5ddb67cf1 100644
--- a/crates/cli/tests/programs/multi/string-utils/src/main.rs
+++ b/crates/cli/tests/programs/multi/string-utils/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/crates/continuations/programs/examples/fibonacci.rs b/crates/continuations/programs/examples/fibonacci.rs
index b907f1a705..37006d6789 100644
--- a/crates/continuations/programs/examples/fibonacci.rs
+++ b/crates/continuations/programs/examples/fibonacci.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::{read, reveal_u64};
diff --git a/crates/continuations/programs/examples/multiple.rs b/crates/continuations/programs/examples/multiple.rs
index d87edc7ab1..e6127160ca 100644
--- a/crates/continuations/programs/examples/multiple.rs
+++ b/crates/continuations/programs/examples/multiple.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::read;
diff --git a/crates/sdk/guest/fib/src/main.rs b/crates/sdk/guest/fib/src/main.rs
index d342f4d3ab..ea4c513e85 100644
--- a/crates/sdk/guest/fib/src/main.rs
+++ b/crates/sdk/guest/fib/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/crates/sdk/guest/little/src/main.rs b/crates/sdk/guest/little/src/main.rs
index 1e47f88689..bbae4d8cf4 100644
--- a/crates/sdk/guest/little/src/main.rs
+++ b/crates/sdk/guest/little/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/crates/sdk/guest/p256/src/main.rs b/crates/sdk/guest/p256/src/main.rs
index e2fae918ad..ada9a98d8f 100644
--- a/crates/sdk/guest/p256/src/main.rs
+++ b/crates/sdk/guest/p256/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/crates/sdk/programs/examples/fibonacci.rs b/crates/sdk/programs/examples/fibonacci.rs
index b907f1a705..37006d6789 100644
--- a/crates/sdk/programs/examples/fibonacci.rs
+++ b/crates/sdk/programs/examples/fibonacci.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::{read, reveal_u64};
diff --git a/crates/sdk/programs/examples/verify-stark.rs b/crates/sdk/programs/examples/verify-stark.rs
index 56698e76f7..2fef3b6f44 100644
--- a/crates/sdk/programs/examples/verify-stark.rs
+++ b/crates/sdk/programs/examples/verify-stark.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/crates/toolchain/build/src/lib.rs b/crates/toolchain/build/src/lib.rs
index 72e547be5e..66bfdb1d2e 100644
--- a/crates/toolchain/build/src/lib.rs
+++ b/crates/toolchain/build/src/lib.rs
@@ -19,16 +19,15 @@ pub use self::config::GuestOptions;
 
 mod config;
 
-/// Custom rustc target for the openvm guest. The JSON spec lives at
-/// `<RUSTC_TARGET>.json` next to this crate.
-pub const RUSTC_TARGET: &str = "riscv64im-openvm-none-elf";
+/// Custom rustc target for the openvm guest.
+pub const RUSTC_TARGET: &str = "riscv64im-unknown-openvm-elf";
 
 /// Directory containing the target JSON; passed to cargo as `RUST_TARGET_PATH`.
 pub fn rustc_target_spec_dir() -> &'static Path {
     Path::new(env!("CARGO_MANIFEST_DIR"))
 }
 /// The default Rust toolchain name to use if OPENVM_RUST_TOOLCHAIN is not set
-pub const DEFAULT_RUSTUP_TOOLCHAIN_NAME: &str = "nightly-2026-01-18";
+pub const DEFAULT_RUSTUP_TOOLCHAIN_NAME: &str = "openvm-rv64";
 
 /// Get the Rust toolchain name from environment variable or default
 pub fn get_rustup_toolchain_name() -> String {
@@ -251,7 +250,8 @@ fn sanitized_cmd(tool: &str) -> Command {
 
 /// Creates a std::process::Command to execute the given cargo
 /// command in an environment suitable for targeting the zkvm guest.
-pub fn cargo_command(subcmd: &str, rust_flags: &[&str]) -> Command {
+/// If `with_std` is true, `std` is added to the `-Zbuild-std` crate list.
+pub fn cargo_command(subcmd: &str, rust_flags: &[&str], with_std: bool) -> Command {
     let toolchain = format!("+{}", get_rustup_toolchain_name());
 
     let rustc = sanitized_cmd("rustup")
@@ -271,12 +271,12 @@ pub fn cargo_command(subcmd: &str, rust_flags: &[&str]) -> Command {
         args.push("--locked");
     }
 
-    args.extend_from_slice(&[
-        "-Z",
-        "build-std=alloc,core,panic_abort",
-        "-Z",
-        "build-std-features=compiler-builtins-mem",
-    ]);
+    let build_std = if with_std {
+        "build-std=alloc,core,panic_abort,std"
+    } else {
+        "build-std=alloc,core,panic_abort"
+    };
+    args.extend_from_slice(&["-Z", build_std, "-Z", "build-std-features=compiler-builtins-mem"]);
 
     println!("Building guest package: cargo {}", args.join(" "));
 
@@ -398,16 +398,23 @@ pub fn build_generic(guest_opts: &GuestOptions) -> Result<PathBuf, Option<i32>>
 
     // Check if the required toolchain and rust-src component are installed, and if not, install
     // them. This requires that `rustup` is installed.
-    if let Err(code) = ensure_toolchain_installed(&get_rustup_toolchain_name(), &["rust-src"]) {
-        eprintln!("rustup toolchain commands failed. Please ensure rustup is installed (https://www.rust-lang.org/tools/install)");
-        return Err(Some(code));
+    // Skip for linked toolchains (e.g. custom-built rustc) where rustup component commands
+    // don't apply — the toolchain is expected to already include rust-src.
+    let toolchain_name = get_rustup_toolchain_name();
+    let is_linked_toolchain = !toolchain_name.contains("nightly") && !toolchain_name.contains("stable") && !toolchain_name.contains("beta");
+    if !is_linked_toolchain {
+        if let Err(code) = ensure_toolchain_installed(&toolchain_name, &["rust-src"]) {
+            eprintln!("rustup toolchain commands failed. Please ensure rustup is installed (https://www.rust-lang.org/tools/install)");
+            return Err(Some(code));
+        }
     }
 
     let target_dir = guest_opts.target_dir.as_ref().unwrap();
     fs::create_dir_all(target_dir).unwrap();
     let rust_flags: Vec<_> = guest_opts.rustc_flags.iter().map(|s| s.as_str()).collect();
 
-    let mut cmd = cargo_command("build", &rust_flags);
+    let with_std = guest_opts.features.iter().any(|f| f == "std");
+    let mut cmd = cargo_command("build", &rust_flags, with_std);
 
     if !guest_opts.features.is_empty() {
         cmd.args(["--features", guest_opts.features.join(",").as_str()]);
diff --git a/crates/toolchain/openvm/src/lib.rs b/crates/toolchain/openvm/src/lib.rs
index 7811ae3f94..9424da3458 100644
--- a/crates/toolchain/openvm/src/lib.rs
+++ b/crates/toolchain/openvm/src/lib.rs
@@ -20,6 +20,8 @@ pub use openvm_riscv_guest::*;
 
 #[cfg(openvm_intrinsics)]
 mod getrandom;
+#[cfg(openvm_intrinsics)]
+mod pal_abi;
 pub mod io;
 pub mod process;
 pub mod serde;
@@ -71,7 +73,7 @@ fn _fault() -> ! {
 ///
 /// fn main() { }
 /// ```
-#[cfg(all(not(feature = "std"), openvm_intrinsics))]
+#[cfg(openvm_intrinsics)]
 #[macro_export]
 macro_rules! entry {
     ($path:path) => {
@@ -88,9 +90,8 @@ macro_rules! entry {
         }
     };
 }
-/// This macro does nothing. You should name the function `main` so that the normal rust main
-/// function setup is used.
-#[cfg(any(feature = "std", not(openvm_intrinsics)))]
+/// This macro does nothing when not compiling for the guest target.
+#[cfg(not(openvm_intrinsics))]
 #[macro_export]
 macro_rules! entry {
     ($path:path) => {};
diff --git a/crates/toolchain/openvm/src/pal_abi.rs b/crates/toolchain/openvm/src/pal_abi.rs
new file mode 100644
index 0000000000..c2ebe374a2
--- /dev/null
+++ b/crates/toolchain/openvm/src/pal_abi.rs
@@ -0,0 +1,234 @@
+/// For rust std library compatibility, we need to define the ABI specified in
+/// <https://github.com/openvm-org/rust/blob/feat/riscv64im-unknown-openvm-elf/library/std/src/sys/pal/openvm/abi.rs>
+/// while we are using target = "riscv64im-unknown-openvm-elf".
+use openvm_platform::{fileno::*, memory::sys_alloc_aligned, rust_rt::terminate, WORD_SIZE};
+use openvm_riscv_guest::{hint_buffer_chunked, hint_random, raw_print_str_from_bytes};
+
+const DIGEST_WORDS: usize = 8;
+
+pub mod exit_code {
+    pub const SUCCESS: u8 = 0;
+    pub const PANIC: u8 = 1;
+    pub const UNIMP: u8 = 2;
+    // Temporarily use 4 to detect if halt is called.
+    pub const HALT: u8 = 4;
+    pub const PAUSE: u8 = 5;
+}
+
+/// # Safety
+///
+/// `out_state` must be aligned and dereferenceable.
+// [inline(never)] is added to mitigate potentially leaking information about program execution
+// through the final value of the program counter (pc) on halt where there is more than one
+// location in the program where `sys_halt` is called. As long as the halt instruction only exists
+// in one place within the program, the pc will always be the same invariant with input.
+#[inline(never)]
+#[no_mangle]
+pub extern "C" fn sys_halt(_user_exit: u8, _out_state: *const [u32; DIGEST_WORDS]) -> ! {
+    terminate::<{ exit_code::HALT }>();
+    unreachable!()
+}
+
+/// Not used
+#[no_mangle]
+pub extern "C" fn sys_output(_output_id: u32, _output_value: u32) {
+    terminate::<{ exit_code::UNIMP }>();
+}
+
+/// # Safety
+///
+/// `out_state`, `in_state`, `block1_ptr`, and `block2_ptr` must be aligned and
+/// dereferenceable.
+#[inline(always)]
+#[no_mangle]
+pub unsafe extern "C" fn sys_sha_compress(
+    _out_state: *mut [u32; DIGEST_WORDS],
+    _in_state: *const [u32; DIGEST_WORDS],
+    _block1_ptr: *const [u32; DIGEST_WORDS],
+    _block2_ptr: *const [u32; DIGEST_WORDS],
+) {
+    unreachable!("sha_compress should not be part of PAL")
+}
+
+/// # Safety
+///
+/// `out_state`, `in_state`, and `buf` must be aligned and dereferenceable.
+#[inline(always)]
+#[no_mangle]
+pub unsafe extern "C" fn sys_sha_buffer(
+    _out_state: *mut [u32; DIGEST_WORDS],
+    _in_state: *const [u32; DIGEST_WORDS],
+    _buf: *const u8,
+    _count: u32,
+) {
+    unreachable!("sha_buffer should not be part of PAL")
+}
+
+/// # Safety
+///
+/// `recv_buf` must be aligned and dereferenceable.
+#[no_mangle]
+pub unsafe extern "C" fn sys_rand(recv_buf: *mut u32, words: usize) {
+    hint_random(words);
+    hint_buffer_chunked(recv_buf as *mut u8, words);
+}
+
+/// # Safety
+///
+/// `msg_ptr` must be aligned and dereferenceable.
+#[no_mangle]
+unsafe extern "C" fn sys_panic(msg_ptr: *const u8, len: usize) -> ! {
+    raw_print_str_from_bytes(msg_ptr, len);
+    terminate::<{ exit_code::PANIC }>();
+    unreachable!()
+}
+
+/// # Safety
+///
+/// `msg_ptr` must be aligned and dereferenceable.
+#[no_mangle]
+pub unsafe extern "C" fn sys_log(msg_ptr: *const u8, len: usize) {
+    raw_print_str_from_bytes(msg_ptr, len);
+}
+
+/// Cycle count
+#[no_mangle]
+pub extern "C" fn sys_cycle_count() -> u64 {
+    crate::io::println("TODO");
+    terminate::<{ exit_code::UNIMP }>();
+    0u64
+}
+
+/// Reads the given number of bytes into the given buffer, posix-style.  Returns
+/// the number of bytes actually read.  On end of file, returns 0.
+///
+/// Like POSIX read, this is not guaranteed to read all bytes
+/// requested.  If we haven't reached EOF, it is however guaranteed to
+/// read at least one byte.
+///
+/// Users should prefer a higher-level abstraction.
+///
+/// # Safety
+///
+/// `recv_ptr` must be aligned and dereferenceable.
+#[no_mangle]
+pub unsafe extern "C" fn sys_read(_fd: u32, _recv_ptr: *mut u8, _nread: usize) -> usize {
+    crate::io::println("sys_read is todo");
+    terminate::<{ exit_code::UNIMP }>();
+    0
+}
+
+/// Reads up to the given number of words into the buffer [recv_buf,
+/// recv_buf + nwords).  Returns the number of bytes actually read.
+/// sys_read_words is a more efficient interface than sys_read, but
+/// varies from POSIX semantics.  Notably:
+///
+/// * The read length is specified in words, not bytes.  (The output
+/// length is still returned in bytes)
+///
+/// * If not all data is available, `sys_read_words` will return a short read.
+///
+/// * recv_buf must be word-aligned.
+///
+/// * Return a short read in the case of EOF mid-way through.
+///
+/// # Safety
+///
+/// `recv_ptr' must be a word-aligned pointer and point to a region of
+/// `nwords' size.
+#[no_mangle]
+pub unsafe extern "C" fn sys_read_words(_fd: u32, _recv_ptr: *mut u32, _nwords: usize) -> usize {
+    crate::io::println("sys_read_words is todo");
+    terminate::<{ exit_code::UNIMP }>();
+    0
+}
+
+/// # Safety
+///
+/// `write_ptr` must be aligned and dereferenceable.
+#[no_mangle]
+pub unsafe extern "C" fn sys_write(fd: u32, write_ptr: *const u8, nbytes: usize) {
+    if fd == STDOUT || fd == STDERR {
+        // We always print to host stdout using UTF-8 encoding.
+        raw_print_str_from_bytes(write_ptr, nbytes);
+    } else {
+        use core::fmt::Write;
+        let mut writer = crate::io::Writer;
+        let _ = write!(writer, "sys_write to fd={fd} not supported.\n");
+        terminate::<{ exit_code::UNIMP }>();
+    }
+}
+
+/// Retrieves the value of an environment variable, and stores as much
+/// of it as it can it in the memory at [out_words, out_words +
+/// out_nwords).
+///
+/// Returns the length of the value, in bytes, or usize::MAX if the variable is
+/// not set.
+///
+/// This is normally called twice to read an environment variable:
+/// Once to get the length of the value, and once to fill in allocated
+/// memory.
+///
+/// NOTE: Repeated calls to sys_getenv are not guaranteed to result in the same
+/// data being returned. Returned data is entirely in the control of the host.
+///
+/// # Safety
+///
+/// `out_words` and `varname` must be aligned and dereferenceable.
+#[no_mangle]
+pub unsafe extern "C" fn sys_getenv(
+    _out_words: *mut u32,
+    _out_nwords: usize,
+    _varname: *const u8,
+    _varname_len: usize,
+) -> usize {
+    crate::io::println("sys_getenv is todo; returning 0");
+    0
+}
+
+/// Retrieves the count of arguments provided to program execution.
+///
+/// NOTE: Repeated calls to sys_argc are not guaranteed to result in the same
+/// data being returned. Returned data is entirely in the control of the host.
+#[no_mangle]
+pub extern "C" fn sys_argc() -> usize {
+    crate::io::println("sys_argc is todo; returning 0");
+    0
+}
+
+/// Retrieves the argument with arg_index, and stores as much
+/// of it as it can it in the memory at [out_words, out_words +
+/// out_nwords).
+///
+/// Returns the length, in bytes, of the argument string. If the requested
+/// argument index does not exist (i.e. `arg_index` >= argc) then this syscall
+/// will not return.
+///
+/// This is normally called twice to read an argument: Once to get the length of
+/// the value, and once to fill in allocated memory.
+///
+/// NOTE: Repeated calls to sys_argv are not guaranteed to result in the same
+/// data being returned. Returned data is entirely in the control of the host.
+///
+/// # Safety
+///
+/// `out_words` must be aligned and dereferenceable.
+#[no_mangle]
+pub unsafe extern "C" fn sys_argv(
+    _out_words: *mut u32,
+    _out_nwords: usize,
+    _arg_index: usize,
+) -> usize {
+    crate::io::println("sys_argv is todo; returning 0");
+    0
+}
+
+/// Deprecated, use `sys_alloc_aligned` instead.
+#[no_mangle]
+#[deprecated]
+pub extern "C" fn sys_alloc_words(nwords: usize) -> *mut u32 {
+    unsafe { sys_alloc_aligned(WORD_SIZE * nwords, WORD_SIZE) as *mut u32 }
+}
+
+// sys_alloc_aligned is already extern no_mangle exported from openvm_platform::memory
diff --git a/crates/toolchain/platform/Cargo.toml b/crates/toolchain/platform/Cargo.toml
index 5f082d2e96..33f0bb7dec 100644
--- a/crates/toolchain/platform/Cargo.toml
+++ b/crates/toolchain/platform/Cargo.toml
@@ -13,7 +13,7 @@ openvm-riscv-guest.workspace = true
 
 # This crate should have as few dependencies as possible so it can be
 # used as many places as possible to share the platform definitions.
-[target.'cfg(all(target_arch = "riscv64", target_os = "none"))'.dependencies]
+[target.'cfg(all(target_arch = "riscv64", any(target_os = "none", target_os = "openvm")))'.dependencies]
 critical-section = { workspace = true, optional = true }
 embedded-alloc = { version = "0.6.0", features = [
     "allocator_api",
diff --git a/examples/algebra/src/main.rs b/examples/algebra/src/main.rs
index 1d521f3f89..54a74b8704 100644
--- a/examples/algebra/src/main.rs
+++ b/examples/algebra/src/main.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/examples/ecc/src/main.rs b/examples/ecc/src/main.rs
index 454cad235c..0bd76a0ee2 100644
--- a/examples/ecc/src/main.rs
+++ b/examples/ecc/src/main.rs
@@ -1,5 +1,5 @@
 // [!region imports]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use hex_literal::hex;
diff --git a/examples/i256/src/main.rs b/examples/i256/src/main.rs
index 04ca7a8445..dee68244ff 100644
--- a/examples/i256/src/main.rs
+++ b/examples/i256/src/main.rs
@@ -1,5 +1,5 @@
 #![allow(clippy::needless_range_loop)]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use core::array;
diff --git a/examples/keccak/src/main.rs b/examples/keccak/src/main.rs
index dc9250b067..715c3ccbd6 100644
--- a/examples/keccak/src/main.rs
+++ b/examples/keccak/src/main.rs
@@ -1,5 +1,5 @@
 // [!region imports]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/examples/pairing/src/main.rs b/examples/pairing/src/main.rs
index 1791e993f1..bef83f4c8c 100644
--- a/examples/pairing/src/main.rs
+++ b/examples/pairing/src/main.rs
@@ -1,5 +1,5 @@
 // [!region pre]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use hex_literal::hex;
diff --git a/examples/sha2/src/main.rs b/examples/sha2/src/main.rs
index 2d73f7afdb..1b14312920 100644
--- a/examples/sha2/src/main.rs
+++ b/examples/sha2/src/main.rs
@@ -1,5 +1,5 @@
 // [!region imports]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/examples/u256/src/main.rs b/examples/u256/src/main.rs
index 67aa120a2b..83f39be29b 100644
--- a/examples/u256/src/main.rs
+++ b/examples/u256/src/main.rs
@@ -1,5 +1,5 @@
 #![allow(clippy::needless_range_loop)]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use core::array;
diff --git a/extensions/algebra/tests/programs/examples/complex_redundant_modulus.rs b/extensions/algebra/tests/programs/examples/complex_redundant_modulus.rs
index a17d3e4d5b..c1c7321bcf 100644
--- a/extensions/algebra/tests/programs/examples/complex_redundant_modulus.rs
+++ b/extensions/algebra/tests/programs/examples/complex_redundant_modulus.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/algebra/tests/programs/examples/complex_secp256k1.rs b/extensions/algebra/tests/programs/examples/complex_secp256k1.rs
index 8ecae56365..041cbad507 100644
--- a/extensions/algebra/tests/programs/examples/complex_secp256k1.rs
+++ b/extensions/algebra/tests/programs/examples/complex_secp256k1.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/algebra/tests/programs/examples/complex_two_moduli.rs b/extensions/algebra/tests/programs/examples/complex_two_moduli.rs
index 752a861301..266e7cbeec 100644
--- a/extensions/algebra/tests/programs/examples/complex_two_moduli.rs
+++ b/extensions/algebra/tests/programs/examples/complex_two_moduli.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/algebra/tests/programs/examples/invalid_setup.rs b/extensions/algebra/tests/programs/examples/invalid_setup.rs
index b9e697f3f5..27e0de7e57 100644
--- a/extensions/algebra/tests/programs/examples/invalid_setup.rs
+++ b/extensions/algebra/tests/programs/examples/invalid_setup.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/algebra/tests/programs/examples/little.rs b/extensions/algebra/tests/programs/examples/little.rs
index d5218c35e6..c68d997975 100644
--- a/extensions/algebra/tests/programs/examples/little.rs
+++ b/extensions/algebra/tests/programs/examples/little.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/algebra/tests/programs/examples/moduli_setup.rs b/extensions/algebra/tests/programs/examples/moduli_setup.rs
index 3ea841d45e..ee05430a33 100644
--- a/extensions/algebra/tests/programs/examples/moduli_setup.rs
+++ b/extensions/algebra/tests/programs/examples/moduli_setup.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/algebra/tests/programs/examples/sqrt.rs b/extensions/algebra/tests/programs/examples/sqrt.rs
index 7f86ab1d0a..d37ebcb32c 100644
--- a/extensions/algebra/tests/programs/examples/sqrt.rs
+++ b/extensions/algebra/tests/programs/examples/sqrt.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/deferral/tests/programs/examples/multiple.rs b/extensions/deferral/tests/programs/examples/multiple.rs
index a85c99edec..f181f591d9 100644
--- a/extensions/deferral/tests/programs/examples/multiple.rs
+++ b/extensions/deferral/tests/programs/examples/multiple.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm_deferral_guest::{deferred_compute, get_deferred_output, Commit};
diff --git a/extensions/deferral/tests/programs/examples/single.rs b/extensions/deferral/tests/programs/examples/single.rs
index f559f84843..140bb6f696 100644
--- a/extensions/deferral/tests/programs/examples/single.rs
+++ b/extensions/deferral/tests/programs/examples/single.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm_deferral_guest::{deferred_compute, get_deferred_output, Commit};
diff --git a/extensions/ecc/tests/programs/examples/decompress.rs b/extensions/ecc/tests/programs/examples/decompress.rs
index 0f833275fb..6673c7d058 100644
--- a/extensions/ecc/tests/programs/examples/decompress.rs
+++ b/extensions/ecc/tests/programs/examples/decompress.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use core::ops::Neg;
diff --git a/extensions/ecc/tests/programs/examples/ec.rs b/extensions/ecc/tests/programs/examples/ec.rs
index 5984674719..8fcc56d0c1 100644
--- a/extensions/ecc/tests/programs/examples/ec.rs
+++ b/extensions/ecc/tests/programs/examples/ec.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use hex_literal::hex;
diff --git a/extensions/ecc/tests/programs/examples/ec_nonzero_a.rs b/extensions/ecc/tests/programs/examples/ec_nonzero_a.rs
index 478d49a351..7599f350e1 100644
--- a/extensions/ecc/tests/programs/examples/ec_nonzero_a.rs
+++ b/extensions/ecc/tests/programs/examples/ec_nonzero_a.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use hex_literal::hex;
diff --git a/extensions/ecc/tests/programs/examples/ec_two_curves.rs b/extensions/ecc/tests/programs/examples/ec_two_curves.rs
index d3d20b8f49..840e53a8f7 100644
--- a/extensions/ecc/tests/programs/examples/ec_two_curves.rs
+++ b/extensions/ecc/tests/programs/examples/ec_two_curves.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use hex_literal::hex;
diff --git a/extensions/ecc/tests/programs/examples/ecdsa.rs b/extensions/ecc/tests/programs/examples/ecdsa.rs
index 775dd919d0..9e05aecaec 100644
--- a/extensions/ecc/tests/programs/examples/ecdsa.rs
+++ b/extensions/ecc/tests/programs/examples/ecdsa.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #![allow(unused_imports)]
 
diff --git a/extensions/ecc/tests/programs/examples/ecdsa_recover_k256.rs b/extensions/ecc/tests/programs/examples/ecdsa_recover_k256.rs
index f1994ba3c3..3a81227e31 100644
--- a/extensions/ecc/tests/programs/examples/ecdsa_recover_k256.rs
+++ b/extensions/ecc/tests/programs/examples/ecdsa_recover_k256.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/ecc/tests/programs/examples/ecdsa_recover_p256.rs b/extensions/ecc/tests/programs/examples/ecdsa_recover_p256.rs
index 988ff5226e..81babb406e 100644
--- a/extensions/ecc/tests/programs/examples/ecdsa_recover_p256.rs
+++ b/extensions/ecc/tests/programs/examples/ecdsa_recover_p256.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/ecc/tests/programs/examples/invalid_setup.rs b/extensions/ecc/tests/programs/examples/invalid_setup.rs
index e29072ae57..03f1380e9b 100644
--- a/extensions/ecc/tests/programs/examples/invalid_setup.rs
+++ b/extensions/ecc/tests/programs/examples/invalid_setup.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm_ecc_guest::CyclicGroup;
diff --git a/extensions/ecc/tests/programs/examples/sec1_decode.rs b/extensions/ecc/tests/programs/examples/sec1_decode.rs
index 31a5053f08..64219fbdb9 100644
--- a/extensions/ecc/tests/programs/examples/sec1_decode.rs
+++ b/extensions/ecc/tests/programs/examples/sec1_decode.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/riscv/tests/programs/examples/collatz.rs b/extensions/riscv/tests/programs/examples/collatz.rs
index f592befffe..5e326aba42 100644
--- a/extensions/riscv/tests/programs/examples/collatz.rs
+++ b/extensions/riscv/tests/programs/examples/collatz.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/extensions/riscv/tests/programs/examples/fibonacci.rs b/extensions/riscv/tests/programs/examples/fibonacci.rs
index 762644c694..31ef048195 100644
--- a/extensions/riscv/tests/programs/examples/fibonacci.rs
+++ b/extensions/riscv/tests/programs/examples/fibonacci.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/extensions/riscv/tests/programs/examples/getrandom.rs b/extensions/riscv/tests/programs/examples/getrandom.rs
index 7664b62960..9e4feb3286 100644
--- a/extensions/riscv/tests/programs/examples/getrandom.rs
+++ b/extensions/riscv/tests/programs/examples/getrandom.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #[cfg(feature = "getrandom-v02")]
 compile_error!("this program is not compatible with getrandom v0.2");
diff --git a/extensions/riscv/tests/programs/examples/getrandom_v02.rs b/extensions/riscv/tests/programs/examples/getrandom_v02.rs
index 70a66dc4f0..7779fd9936 100644
--- a/extensions/riscv/tests/programs/examples/getrandom_v02.rs
+++ b/extensions/riscv/tests/programs/examples/getrandom_v02.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #[cfg(feature = "getrandom")]
 compile_error!("this program is not compatible with getrandom v0.2");
diff --git a/extensions/riscv/tests/programs/examples/hashmap.rs b/extensions/riscv/tests/programs/examples/hashmap.rs
index 2968f4761d..cfed27a682 100644
--- a/extensions/riscv/tests/programs/examples/hashmap.rs
+++ b/extensions/riscv/tests/programs/examples/hashmap.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/extensions/riscv/tests/programs/examples/heap_overflow.rs b/extensions/riscv/tests/programs/examples/heap_overflow.rs
index 080b15296b..070f12ad56 100644
--- a/extensions/riscv/tests/programs/examples/heap_overflow.rs
+++ b/extensions/riscv/tests/programs/examples/heap_overflow.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use alloc::vec;
diff --git a/extensions/riscv/tests/programs/examples/hint.rs b/extensions/riscv/tests/programs/examples/hint.rs
index 42d9ec6044..f3871891a6 100644
--- a/extensions/riscv/tests/programs/examples/hint.rs
+++ b/extensions/riscv/tests/programs/examples/hint.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 use openvm::io::read_vec;
 
diff --git a/extensions/riscv/tests/programs/examples/hint_large_buffer.rs b/extensions/riscv/tests/programs/examples/hint_large_buffer.rs
index 0f8507e94e..8558b358d3 100644
--- a/extensions/riscv/tests/programs/examples/hint_large_buffer.rs
+++ b/extensions/riscv/tests/programs/examples/hint_large_buffer.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::read_vec;
diff --git a/extensions/riscv/tests/programs/examples/load_x0.rs b/extensions/riscv/tests/programs/examples/load_x0.rs
index f281b625dd..3ce1cf6c4f 100644
--- a/extensions/riscv/tests/programs/examples/load_x0.rs
+++ b/extensions/riscv/tests/programs/examples/load_x0.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use core::arch::asm;
diff --git a/extensions/riscv/tests/programs/examples/print.rs b/extensions/riscv/tests/programs/examples/print.rs
index d5d077a5dd..1043107ff0 100644
--- a/extensions/riscv/tests/programs/examples/print.rs
+++ b/extensions/riscv/tests/programs/examples/print.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::print;
diff --git a/extensions/riscv/tests/programs/examples/read.rs b/extensions/riscv/tests/programs/examples/read.rs
index bd861383ed..4f8ce9b736 100644
--- a/extensions/riscv/tests/programs/examples/read.rs
+++ b/extensions/riscv/tests/programs/examples/read.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 extern crate alloc;
 use openvm::io::read;
diff --git a/extensions/riscv/tests/programs/examples/reveal.rs b/extensions/riscv/tests/programs/examples/reveal.rs
index 886dd54691..cb3aff3b6d 100644
--- a/extensions/riscv/tests/programs/examples/reveal.rs
+++ b/extensions/riscv/tests/programs/examples/reveal.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::{reveal_bytes32, reveal_u64};
diff --git a/extensions/riscv/tests/programs/examples/tiny-mem-test.rs b/extensions/riscv/tests/programs/examples/tiny-mem-test.rs
index c0b0ecaf4e..e75438def4 100644
--- a/extensions/riscv/tests/programs/examples/tiny-mem-test.rs
+++ b/extensions/riscv/tests/programs/examples/tiny-mem-test.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 extern crate alloc;
 use alloc::vec::Vec;
diff --git a/guest-libs/ff_derive/tests/programs/examples/batch_inversion.rs b/guest-libs/ff_derive/tests/programs/examples/batch_inversion.rs
index c1fdc2e6ec..b8f164a1f6 100644
--- a/guest-libs/ff_derive/tests/programs/examples/batch_inversion.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/batch_inversion.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 openvm::entry!(main);
 
diff --git a/guest-libs/ff_derive/tests/programs/examples/constants.rs b/guest-libs/ff_derive/tests/programs/examples/constants.rs
index 1feb22b307..a6e62df17f 100644
--- a/guest-libs/ff_derive/tests/programs/examples/constants.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/constants.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 openvm::entry!(main);
 
diff --git a/guest-libs/ff_derive/tests/programs/examples/fermat.rs b/guest-libs/ff_derive/tests/programs/examples/fermat.rs
index 41d2526df8..8e552f2a62 100644
--- a/guest-libs/ff_derive/tests/programs/examples/fermat.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/fermat.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 openvm::entry!(main);
diff --git a/guest-libs/ff_derive/tests/programs/examples/from_u128.rs b/guest-libs/ff_derive/tests/programs/examples/from_u128.rs
index 7bc6c4c141..7bdf55452f 100644
--- a/guest-libs/ff_derive/tests/programs/examples/from_u128.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/from_u128.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 openvm::entry!(main);
 
diff --git a/guest-libs/ff_derive/tests/programs/examples/full_limbs.rs b/guest-libs/ff_derive/tests/programs/examples/full_limbs.rs
index 0b5580c029..0ce06099d6 100644
--- a/guest-libs/ff_derive/tests/programs/examples/full_limbs.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/full_limbs.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 openvm::entry!(main);
 
diff --git a/guest-libs/ff_derive/tests/programs/examples/operations.rs b/guest-libs/ff_derive/tests/programs/examples/operations.rs
index fa9d47f25b..9b85738518 100644
--- a/guest-libs/ff_derive/tests/programs/examples/operations.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/operations.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 openvm::entry!(main);
 
diff --git a/guest-libs/ff_derive/tests/programs/examples/sqrt.rs b/guest-libs/ff_derive/tests/programs/examples/sqrt.rs
index 52a80248bb..c0b4f227bb 100644
--- a/guest-libs/ff_derive/tests/programs/examples/sqrt.rs
+++ b/guest-libs/ff_derive/tests/programs/examples/sqrt.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 openvm::entry!(main);
 
diff --git a/guest-libs/k256/tests/programs/examples/add.rs b/guest-libs/k256/tests/programs/examples/add.rs
index db97d1b462..23fd907827 100644
--- a/guest-libs/k256/tests/programs/examples/add.rs
+++ b/guest-libs/k256/tests/programs/examples/add.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{group::Curve, CurveArithmetic, Group};
diff --git a/guest-libs/k256/tests/programs/examples/ecdsa.rs b/guest-libs/k256/tests/programs/examples/ecdsa.rs
index 1305ccf213..797e2c5fda 100644
--- a/guest-libs/k256/tests/programs/examples/ecdsa.rs
+++ b/guest-libs/k256/tests/programs/examples/ecdsa.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/k256/tests/programs/examples/linear_combination.rs b/guest-libs/k256/tests/programs/examples/linear_combination.rs
index ff24b93cab..1bba368a22 100644
--- a/guest-libs/k256/tests/programs/examples/linear_combination.rs
+++ b/guest-libs/k256/tests/programs/examples/linear_combination.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{ops::LinearCombination, Group, PrimeField};
diff --git a/guest-libs/k256/tests/programs/examples/mul.rs b/guest-libs/k256/tests/programs/examples/mul.rs
index 2d8e7a9d08..f0798a9bd1 100644
--- a/guest-libs/k256/tests/programs/examples/mul.rs
+++ b/guest-libs/k256/tests/programs/examples/mul.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{CurveArithmetic, Group, PrimeField};
diff --git a/guest-libs/k256/tests/programs/examples/scalar_sqrt.rs b/guest-libs/k256/tests/programs/examples/scalar_sqrt.rs
index 4392fc01da..af30c788e7 100644
--- a/guest-libs/k256/tests/programs/examples/scalar_sqrt.rs
+++ b/guest-libs/k256/tests/programs/examples/scalar_sqrt.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{CurveArithmetic, Field, PrimeField};
diff --git a/guest-libs/keccak256/tests/programs/examples/keccak.rs b/guest-libs/keccak256/tests/programs/examples/keccak.rs
index 6d02324dfc..8c91bc202e 100644
--- a/guest-libs/keccak256/tests/programs/examples/keccak.rs
+++ b/guest-libs/keccak256/tests/programs/examples/keccak.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/p256/tests/programs/examples/add.rs b/guest-libs/p256/tests/programs/examples/add.rs
index 0f4ae63854..16dde04d58 100644
--- a/guest-libs/p256/tests/programs/examples/add.rs
+++ b/guest-libs/p256/tests/programs/examples/add.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{group::Curve, CurveArithmetic, Group};
diff --git a/guest-libs/p256/tests/programs/examples/ecdsa.rs b/guest-libs/p256/tests/programs/examples/ecdsa.rs
index 4447de455b..6d9193db0c 100644
--- a/guest-libs/p256/tests/programs/examples/ecdsa.rs
+++ b/guest-libs/p256/tests/programs/examples/ecdsa.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/p256/tests/programs/examples/linear_combination.rs b/guest-libs/p256/tests/programs/examples/linear_combination.rs
index fd31ddadec..bcc31fbcc6 100644
--- a/guest-libs/p256/tests/programs/examples/linear_combination.rs
+++ b/guest-libs/p256/tests/programs/examples/linear_combination.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{ops::LinearCombination, Group, PrimeField};
diff --git a/guest-libs/p256/tests/programs/examples/mul.rs b/guest-libs/p256/tests/programs/examples/mul.rs
index 7c05d962a2..855fa63045 100644
--- a/guest-libs/p256/tests/programs/examples/mul.rs
+++ b/guest-libs/p256/tests/programs/examples/mul.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{CurveArithmetic, Group, PrimeField};
diff --git a/guest-libs/p256/tests/programs/examples/scalar_sqrt.rs b/guest-libs/p256/tests/programs/examples/scalar_sqrt.rs
index 045afe89a8..785fb5287d 100644
--- a/guest-libs/p256/tests/programs/examples/scalar_sqrt.rs
+++ b/guest-libs/p256/tests/programs/examples/scalar_sqrt.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use elliptic_curve::{CurveArithmetic, Field, PrimeField};
diff --git a/guest-libs/pairing/tests/programs/examples/bls_ec.rs b/guest-libs/pairing/tests/programs/examples/bls_ec.rs
index 63ce641a75..d29433b551 100644
--- a/guest-libs/pairing/tests/programs/examples/bls_ec.rs
+++ b/guest-libs/pairing/tests/programs/examples/bls_ec.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #[allow(unused_imports)]
diff --git a/guest-libs/pairing/tests/programs/examples/bls_final_exp_hint.rs b/guest-libs/pairing/tests/programs/examples/bls_final_exp_hint.rs
index a96d9e90d0..eadf0b2a8d 100644
--- a/guest-libs/pairing/tests/programs/examples/bls_final_exp_hint.rs
+++ b/guest-libs/pairing/tests/programs/examples/bls_final_exp_hint.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/pairing/tests/programs/examples/bn_ec.rs b/guest-libs/pairing/tests/programs/examples/bn_ec.rs
index 922c537171..ddd138dd5b 100644
--- a/guest-libs/pairing/tests/programs/examples/bn_ec.rs
+++ b/guest-libs/pairing/tests/programs/examples/bn_ec.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #[allow(unused_imports)]
diff --git a/guest-libs/pairing/tests/programs/examples/bn_final_exp_hint.rs b/guest-libs/pairing/tests/programs/examples/bn_final_exp_hint.rs
index 1a1a02ba48..f83a4f0a60 100644
--- a/guest-libs/pairing/tests/programs/examples/bn_final_exp_hint.rs
+++ b/guest-libs/pairing/tests/programs/examples/bn_final_exp_hint.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/pairing/tests/programs/examples/fp12_mul.rs b/guest-libs/pairing/tests/programs/examples/fp12_mul.rs
index 031b793cd3..e08841f2b1 100644
--- a/guest-libs/pairing/tests/programs/examples/fp12_mul.rs
+++ b/guest-libs/pairing/tests/programs/examples/fp12_mul.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #![allow(unused_imports)]
 
diff --git a/guest-libs/pairing/tests/programs/examples/pairing_check.rs b/guest-libs/pairing/tests/programs/examples/pairing_check.rs
index 9e19684200..15311149ce 100644
--- a/guest-libs/pairing/tests/programs/examples/pairing_check.rs
+++ b/guest-libs/pairing/tests/programs/examples/pairing_check.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #![allow(unused_imports)]
 
diff --git a/guest-libs/pairing/tests/programs/examples/pairing_check_fallback.rs b/guest-libs/pairing/tests/programs/examples/pairing_check_fallback.rs
index 1a9fecaf6c..149ba0638d 100644
--- a/guest-libs/pairing/tests/programs/examples/pairing_check_fallback.rs
+++ b/guest-libs/pairing/tests/programs/examples/pairing_check_fallback.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #![allow(unused_imports)]
 
diff --git a/guest-libs/pairing/tests/programs/examples/pairing_line.rs b/guest-libs/pairing/tests/programs/examples/pairing_line.rs
index 2790d7c2e7..5890483c10 100644
--- a/guest-libs/pairing/tests/programs/examples/pairing_line.rs
+++ b/guest-libs/pairing/tests/programs/examples/pairing_line.rs
@@ -1,5 +1,5 @@
 #![allow(unused_imports)]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::read_vec;
diff --git a/guest-libs/pairing/tests/programs/examples/pairing_miller_loop.rs b/guest-libs/pairing/tests/programs/examples/pairing_miller_loop.rs
index f40b830e91..bc2484bcad 100644
--- a/guest-libs/pairing/tests/programs/examples/pairing_miller_loop.rs
+++ b/guest-libs/pairing/tests/programs/examples/pairing_miller_loop.rs
@@ -1,5 +1,5 @@
 #![allow(unused_imports)]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/pairing/tests/programs/examples/pairing_miller_step.rs b/guest-libs/pairing/tests/programs/examples/pairing_miller_step.rs
index 726420f4d2..bc368cccc6 100644
--- a/guest-libs/pairing/tests/programs/examples/pairing_miller_step.rs
+++ b/guest-libs/pairing/tests/programs/examples/pairing_miller_step.rs
@@ -1,5 +1,5 @@
 #![allow(unused_imports)]
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::read_vec;
diff --git a/guest-libs/sha2/tests/programs/examples/sha2.rs b/guest-libs/sha2/tests/programs/examples/sha2.rs
index 3f106e4239..4c639dce64 100644
--- a/guest-libs/sha2/tests/programs/examples/sha2.rs
+++ b/guest-libs/sha2/tests/programs/examples/sha2.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
diff --git a/guest-libs/sha2/tests/programs/examples/sha2_reset.rs b/guest-libs/sha2/tests/programs/examples/sha2_reset.rs
index 56a20100cb..412f08ad3d 100644
--- a/guest-libs/sha2/tests/programs/examples/sha2_reset.rs
+++ b/guest-libs/sha2/tests/programs/examples/sha2_reset.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "none", no_main)]
+#![cfg_attr(any(target_os = "none", target_os = "openvm"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm_sha2::{Digest, Sha256, Sha384, Sha512};