diff --git a/image_format/disk.py b/image_format/disk.py
index 2d1fe172..6af0e0a1 100755
--- a/image_format/disk.py
+++ b/image_format/disk.py
@@ -339,7 +339,7 @@ def main(argv: list[str] | None = None) -> None:
 
         seed = (
             uuid.UUID(spec["seed"])
-            if spec["seed"]
+            if spec["seed"] is not None
             else _derived_seed(spec["identity"], raw_definitions, partitions)
         )
         out = Path(spec["out"]) if spec["out"] else None
diff --git a/image_format/sysext.py b/image_format/sysext.py
index 501592b9..5daba9d9 100755
--- a/image_format/sysext.py
+++ b/image_format/sysext.py
@@ -125,7 +125,7 @@ def main(argv: list[str] | None = None) -> None:
 
         seed = (
             uuid.UUID(spec["seed"])
-            if spec["seed"]
+            if spec["seed"] is not None
             else _derived_seed(spec["identity"], spec["name"], release)
         )
         cmd = [