diff --git a/stages/org.osbuild.ostree.config b/stages/org.osbuild.ostree.config
index e9241b8a..2b799aa0 100755
--- a/stages/org.osbuild.ostree.config
+++ b/stages/org.osbuild.ostree.config
@@ -63,13 +63,16 @@ def ostree(*args, _input=None, **kwargs):
 
 def main(tree, options):
     repo = os.path.join(tree, options["repo"].lstrip("/"))
-    config = options["config"]
+    sysroot_options = options["config"].get("sysroot", {})
 
-    for group, items in config.items():
-        for key, value in items.items():
-            name = f"{group}.{key}"
-            ostree("config", "set", name, str(value),
-                   repo=repo)
+    bootloader = sysroot_options.get("bootloader")
+    if bootloader:
+        ostree("config", "set", "sysroot.bootloader", bootloader, repo=repo)
+
+    readonly = sysroot_options.get("readonly")
+    if readonly is not None:  # can be False, which we would want to set
+        ro = "true" if readonly else "false"
+        ostree("config", "set", "sysroot.readonly", ro, repo=repo)
 
 
 if __name__ == '__main__':