diff --git a/nixos/modules/system/etc/build-composefs-dump.py b/nixos/modules/system/etc/build-composefs-dump.py
index bf4ec791ecf7..bba454dd888d 100644
--- a/nixos/modules/system/etc/build-composefs-dump.py
+++ b/nixos/modules/system/etc/build-composefs-dump.py
@@ -199,7 +199,8 @@ def main() -> None:
                         size=os.stat(source).st_size,
                         filetype=FileType.file,
                         mode=mode,
-                        payload=target,
+                        # payload needs to be relative path in this case
+                        payload=target.lstrip("/"),
                     )
             paths[target] = composefs_path
             add_leading_directories(target, attrs, paths)