diff --git a/heracles/healpy.py b/heracles/healpy.py
index 4b74ae7..cce77b0 100644
--- a/heracles/healpy.py
+++ b/heracles/healpy.py
@@ -198,7 +198,7 @@ def transform(self, data: NDArray[Any], spin: int = 0) -> NDArray[Any]:
         if spin != 0:
             alm = alm[1:].copy()
 
-        update_metadata(alm, **md, deconv=self.__deconv)
+        update_metadata(alm, **{**md, "deconv": self.__deconv})
 
         return alm