diff --git a/utils/fasm2frames.py b/utils/fasm2frames.py
index 6fe2c7bd..d0b16af3 100755
--- a/utils/fasm2frames.py
+++ b/utils/fasm2frames.py
@@ -154,12 +154,13 @@ def run(
         assembler.mark_roi_frames(Roi(db=db, x1=x1, x2=x2, y1=y1, y2=y2))
 
         if 'required_features' in roi_j:
-            extra_features = fasm.parse_fasm_string(
-                '\n'.join(roi_j['required_features']))
+            extra_features = list(
+                fasm.parse_fasm_string('\n'.join(roi_j['required_features'])))
 
     # Get required extra features for the part
     required_features = db.get_required_fasm_features(part)
-    extra_features += fasm.parse_fasm_string('\n'.join(required_features))
+    extra_features += list(
+        fasm.parse_fasm_string('\n'.join(required_features)))
 
     assembler.parse_fasm_filename(filename_in, extra_features=extra_features)