--- zzzz-none-000/linux-4.9.231/drivers/mtd/mtdchar.c	2020-07-22 07:10:54.000000000 +0000
+++ falcon-5590-729/linux-4.9.231/drivers/mtd/mtdchar.c	2022-03-30 12:03:34.000000000 +0000
@@ -1063,6 +1063,9 @@
 {
 	int ret;
 
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
 	mutex_lock(&mtd_mutex);
 	ret = mtdchar_ioctl(file, cmd, arg);
 	mutex_unlock(&mtd_mutex);
@@ -1089,6 +1092,9 @@
 	void __user *argp = compat_ptr(arg);
 	int ret = 0;
 
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
 	mutex_lock(&mtd_mutex);
 
 	switch (cmd) {