--- zzzz-none-000/linux-4.1.52/drivers/mtd/ubi/vmt.c	2018-05-28 02:26:45.000000000 +0000
+++ bcm63-7530ax-731/linux-4.1.52/drivers/mtd/ubi/vmt.c	2022-03-02 11:37:13.000000000 +0000
@@ -413,6 +413,10 @@
 	struct ubi_device *ubi = vol->ubi;
 	int i, err, vol_id = vol->vol_id, reserved_pebs = vol->reserved_pebs;
 
+#if defined(CONFIG_BCM_KF_KERN_WARNING)
+	err = -EPERM;
+#endif
+
 	dbg_gen("remove device %d, volume %d", ubi->ubi_num, vol_id);
 	ubi_assert(desc->mode == UBI_EXCLUSIVE);
 	ubi_assert(vol == ubi->volumes[vol_id]);
@@ -458,6 +462,11 @@
 	if (!no_vtbl)
 		self_check_volumes(ubi);
 
+#if defined(CONFIG_BCM_KF_KERN_WARNING)
+	if (err == -EPERM) {
+		printk("vmt.c: ubi_remove_volume really returned an undefined error\n");
+	}
+#endif
 	return err;
 
 out_err: