diff --git a/libmat2/subprocess.py b/libmat2/subprocess.py
index 5da393f452884df0456272d3b1bbab2f95462937..fb6fc9dd4b57ed6a4a6e281893fb653020836b90 100644
--- a/libmat2/subprocess.py
+++ b/libmat2/subprocess.py
@@ -51,7 +51,7 @@ def _get_bwrap_args(tempdir: str,
         ['--dev', '/dev',
          '--proc', '/proc',
          '--chdir', cwd,
-         '--tmpfs /tmp',
+         '--tmpfs', '/tmp',
          '--unshare-user-try',
          '--unshare-ipc',
          '--unshare-pid',
@@ -59,7 +59,7 @@ def _get_bwrap_args(tempdir: str,
          '--unshare-uts',
          '--unshare-cgroup-try',
          '--new-session',
-         '--cap-drop all',
+         '--cap-drop', 'all',
          # XXX: enable --die-with-parent once all supported platforms have
          # a bubblewrap recent enough to support it.
          # '--die-with-parent',