--- zzzz-none-000/linux-2.6.39.4/arch/x86/mm/init.c	2011-08-03 19:43:28.000000000 +0000
+++ puma6-atom-6490-729/linux-2.6.39.4/arch/x86/mm/init.c	2021-11-10 13:38:14.000000000 +0000
@@ -373,8 +373,38 @@
 #endif
 }
 
+#ifdef CONFIG_AVM_ENHANCED
+static int root_dev_setup_allowed = 1;
+
+/* As setup_root_dev_if_possible is initially allowed to use
+ * __init root_dev_setup() but may not be defined as __init since it is
+ * reference by the puma6_mtd_add_notifier() hook, thus marked with __ref. */
+int __ref setup_root_dev_if_possible(char *root_device)
+{
+	extern int root_dev_setup_allowed;
+	extern int root_dev_setup(char *);
+
+	if (likely(root_dev_setup_allowed))
+		return root_dev_setup(root_device);
+	else
+		BUG();
+	return -ENOSYS;
+}
+#endif
+
+
+static void disable_setup_root_dev_hook(void)
+{
+#ifdef CONFIG_AVM_ENHANCED
+	root_dev_setup_allowed = 0;
+#endif
+}
+
+
 void free_initmem(void)
 {
+	disable_setup_root_dev_hook();
+
 	free_init_pages("unused kernel memory",
 			(unsigned long)(&__init_begin),
 			(unsigned long)(&__init_end));