diff --git a/HOW.optimus b/HOW.optimus
index 71425bf..86274ac 100644
--- a/HOW.optimus
+++ b/HOW.optimus
@@ -53,9 +53,11 @@
 done
 type=barebox
 for n in $binaries/barebox_unsigned_*.bin; do
-	signed=$(echo $n | sed -e 's/_unsigned_/_signed_/')
-	blaze run -- //isp/fiber/drm:code_sign_tool sign-image $n \
-          --image_type=$type --outfile=$signed --keystore_config_id=$keystore_id
+	if [[ "$n" == *"_release"* ]] || [ "$target" != "spacecast" ]; then
+		signed=$(echo $n | sed -e 's/_unsigned_/_signed_/')
+		blaze run -- //isp/fiber/drm:code_sign_tool sign-image $n \
+		  --image_type=$type --outfile=$signed --keystore_config_id=$keystore_id
+	fi
 done
 
 blaze --batch run //isp/fiber/drm:drm_keystore_client -- \