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mtd: base-files: Unify dual-firmware devices (Linksys)

Consistently handle boot-count reset and upgrade across
ipq40xx, ipq806x, kirkwood, mvebu

Dual-firmware devices often utilize a specific MTD partition
to record the number of times the boot loader has initiated boot.

Most of these devices are NAND, typically with a 2k erase size.
When this code was ported to the ipq40xx platform, the device in hand
used NOR for this partition, with a 16-byte "record" size. As the
implementation of `mtd resetbc` is by-platform, the hard-coded nature
of this change prevented proper operation of a NAND-based device.

* Unified the "NOR" variant with the rest of the Linksys variants

* Added logging to indicate success and failure

* Provided a meaningful return value for scripting

* "Protected" the use of `mtd resetbc` in start-up scripts so that
   failure does not end the boot sequence

* Moved Linksys-specific actions into common `/etc/init.d/bootcount`

For upgrade, these devices need to determine which partition to flash,
as well as set certain U-Boot envirnment variables to change the next
boot to the newly flashed version.

* Moved upgrade-related environment changes out of bootcount

* Combined multiple flashes of environment into single one

* Current-partition detection now handles absence of `boot_part`

Runtime-tested: Linksys EA8300

Signed-off-by: Jeff Kletsky <[email protected]>
Signed-off-by: Christian Lamparter <[email protected]>
[checkpatch.pl fixes, traded split strings for 80+ chars per line]
Jeff Kletsky 6 years ago
parent
commit
b3770eaca3

+ 1 - 1
package/system/mtd/src/Makefile

@@ -16,7 +16,7 @@ obj.ramips = $(obj.seama) $(obj.tpl) $(obj.wrg)
 obj.mvebu = linksys_bootcount.o
 obj.kirkwood = linksys_bootcount.o
 obj.ipq806x = linksys_bootcount.o
-obj.ipq40xx = linksys_bootcount_fix.o
+obj.ipq40xx = linksys_bootcount.o
 
 ifdef FIS_SUPPORT
   obj += fis.o

+ 90 - 18
package/system/mtd/src/linksys_bootcount.c

@@ -2,6 +2,7 @@
  * Linksys boot counter reset code for mtd
  *
  * Copyright (C) 2013 Jonas Gorski <[email protected]>
+ * Portions Copyright (c) 2019, Jeff Kletsky
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License v2
@@ -29,6 +30,7 @@
 #include <string.h>
 #include <errno.h>
 #include <stdint.h>
+#include <syslog.h>
 
 #include <sys/ioctl.h>
 #include <mtd/mtd-user.h>
@@ -37,6 +39,30 @@
 
 #define BOOTCOUNT_MAGIC	0x20110811
 
+/*
+ * EA6350v3, and potentially other NOR-boot devices,
+ * use an offset increment of 16 between records,
+ * not mtd_info_user.writesize (often 1 on NOR devices).
+ */
+
+#define BC_OFFSET_INCREMENT_MIN 16
+
+
+
+#define DLOG_OPEN()
+
+#define DLOG_ERR(...) do {						       \
+		fprintf(stderr, "ERROR: " __VA_ARGS__); fprintf(stderr, "\n"); \
+	} while (0)
+
+#define DLOG_NOTICE(...) do {						\
+		fprintf(stderr, __VA_ARGS__); fprintf(stderr, "\n");	\
+	} while (0)
+
+#define DLOG_DEBUG(...)
+
+
+
 struct bootcounter {
 	uint32_t magic;
 	uint32_t count;
@@ -50,25 +76,50 @@ int mtd_resetbc(const char *mtd)
 	struct mtd_info_user mtd_info;
 	struct bootcounter *curr = (struct bootcounter *)page;
 	unsigned int i;
+	unsigned int bc_offset_increment;
 	int last_count = 0;
 	int num_bc;
 	int fd;
 	int ret;
+	int retval = 0;
+
+	DLOG_OPEN();
 
 	fd = mtd_check_open(mtd);
 
 	if (ioctl(fd, MEMGETINFO, &mtd_info) < 0) {
-		fprintf(stderr, "failed to get mtd info!\n");
-		return -1;
+		DLOG_ERR("Unable to obtain mtd_info for given partition name.");
+
+		retval = -1;
+		goto out;
+	}
+
+
+	/* Detect need to override increment (for EA6350v3) */
+
+	if (mtd_info.writesize < BC_OFFSET_INCREMENT_MIN) {
+
+		bc_offset_increment = BC_OFFSET_INCREMENT_MIN;
+		DLOG_DEBUG("Offset increment set to %i for writesize of %i",
+			   bc_offset_increment, mtd_info.writesize);
+	} else {
+
+		bc_offset_increment = mtd_info.writesize;
 	}
 
-	num_bc = mtd_info.size / mtd_info.writesize;
+	num_bc = mtd_info.size / bc_offset_increment;
 
 	for (i = 0; i < num_bc; i++) {
-		pread(fd, curr, sizeof(*curr), i * mtd_info.writesize);
+		pread(fd, curr, sizeof(*curr), i * bc_offset_increment);
+
+		/* Existing code assumes erase is to 0xff; left as-is (2019) */
 
-		if (curr->magic != BOOTCOUNT_MAGIC && curr->magic != 0xffffffff) {
-			fprintf(stderr, "unexpected magic %08x, bailing out\n", curr->magic);
+		if (curr->magic != BOOTCOUNT_MAGIC &&
+		    curr->magic != 0xffffffff) {
+			DLOG_ERR("Unexpected magic %08x at offset %08x; aborting.",
+				 curr->magic, i * bc_offset_increment);
+
+			retval = -2;
 			goto out;
 		}
 
@@ -78,38 +129,59 @@ int mtd_resetbc(const char *mtd)
 		last_count = curr->count;
 	}
 
-	/* no need to do writes when last boot count is already 0 */
-	if (last_count == 0)
+
+	if (last_count == 0) {	/* bootcount is already 0 */
+
+		retval = 0;
 		goto out;
+	}
 
 
 	if (i == num_bc) {
+		DLOG_NOTICE("Boot-count log full with %i entries; erasing (expected occasionally).",
+			    i);
+
 		struct erase_info_user erase_info;
 		erase_info.start = 0;
 		erase_info.length = mtd_info.size;
 
-		/* erase block */
 		ret = ioctl(fd, MEMERASE, &erase_info);
 		if (ret < 0) {
-			fprintf(stderr, "failed to erase block: %i\n", ret);
-			return -1;
+			DLOG_ERR("Failed to erase boot-count log MTD; ioctl() MEMERASE returned %i",
+				 ret);
+
+			retval = -3;
+			goto out;
 		}
 
 		i = 0;
 	}
 
-	memset(curr, 0xff, mtd_info.writesize);
+	memset(curr, 0xff, bc_offset_increment);
 
 	curr->magic = BOOTCOUNT_MAGIC;
 	curr->count = 0;
 	curr->checksum = BOOTCOUNT_MAGIC;
 
-	ret = pwrite(fd, curr, mtd_info.writesize, i * mtd_info.writesize);
-	if (ret < 0)
-		fprintf(stderr, "failed to write: %i\n", ret);
-	sync();
+	/* Assumes bc_offset_increment is a multiple of mtd_info.writesize */
+
+	ret = pwrite(fd, curr, bc_offset_increment, i * bc_offset_increment);
+	if (ret < 0) {
+		DLOG_ERR("Failed to write boot-count log entry; pwrite() returned %i",
+			 errno);
+		retval = -4;
+		goto out;
+
+	} else {
+		sync();
+
+		DLOG_NOTICE("Boot count sucessfully reset to zero.");
+
+		retval = 0;
+		goto out;
+	}
+
 out:
 	close(fd);
-
-	return 0;
+	return retval;
 }

+ 0 - 115
package/system/mtd/src/linksys_bootcount_fix.c

@@ -1,115 +0,0 @@
-/*
- * Linksys boot counter reset code for mtd
- *
- * Copyright (C) 2013 Jonas Gorski <[email protected]>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License v2
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <stddef.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <endian.h>
-#include <string.h>
-#include <errno.h>
-#include <stdint.h>
-
-#include <sys/ioctl.h>
-#include <mtd/mtd-user.h>
-
-#include "mtd.h"
-
-#define BOOTCOUNT_MAGIC	0x20110811
-
-struct bootcounter {
-	uint32_t magic;
-	uint32_t count;
-	uint32_t checksum;
-};
-
-static char page[2048];
-
-int mtd_resetbc(const char *mtd)
-{
-	struct mtd_info_user mtd_info;
-	struct bootcounter *curr = (struct bootcounter *)page;
-	unsigned int i;
-	int last_count = 0;
-	int num_bc;
-	int fd;
-	int ret;
-
-	fd = mtd_check_open(mtd);
-
-	if (ioctl(fd, MEMGETINFO, &mtd_info) < 0) {
-		fprintf(stderr, "failed to get mtd info!\n");
-		return -1;
-	}
-
-	num_bc = mtd_info.size / 16;
-
-	for (i = 0; i < num_bc; i++) {
-		pread(fd, curr, sizeof(*curr), i * 16);
-
-		if (curr->magic != (BOOTCOUNT_MAGIC) && curr->magic != 0xffffffff) {
-			fprintf(stderr, "unexpected magic %08x, bailing out\n", curr->magic);
-			goto out;
-		}
-
-		if (curr->magic == 0xffffffff)
-			break;
-
-		last_count = curr->count;
-	}
-
-	/* no need to do writes when last boot count is already 0 */
-	if (last_count == 0)
-		goto out;
-
-
-	if (i == num_bc) {
-		struct erase_info_user erase_info;
-		erase_info.start = 0;
-		erase_info.length = mtd_info.size;
-
-		/* erase block */
-		ret = ioctl(fd, MEMERASE, &erase_info);
-		if (ret < 0) {
-			fprintf(stderr, "failed to erase block: %i\n", ret);
-			return -1;
-		}
-
-		i = 0;
-	}
-
-	memset(curr, 0xff, 16);
-
-	curr->magic = BOOTCOUNT_MAGIC;
-	curr->count = 0;
-	curr->checksum = BOOTCOUNT_MAGIC;
-
-	ret = pwrite(fd, curr, 16, i * 16);
-	if (ret < 0)
-		fprintf(stderr, "failed to write: %i\n", ret);
-	sync();
-out:
-	close(fd);
-
-	return 0;
-}

+ 3 - 0
target/linux/ipq40xx/base-files/etc/init.d/bootcount

@@ -10,5 +10,8 @@ start() {
 		[ -n "$(fw_printenv bootcount changed 2>/dev/null)" ] &&\
 			echo -e "bootcount\nchanged\n" | /usr/sbin/fw_setenv -s -
 		;;
+	linksys,ea6350v3)
+		mtd resetbc s_env || true
+		;;
 	esac
 }

+ 0 - 34
target/linux/ipq40xx/base-files/etc/init.d/zlinksys_recovery

@@ -1,34 +0,0 @@
-#!/bin/sh /etc/rc.common
-#
-# This script sets auto_recovery to "yes" and resets the boot counter to 0.
-# As a golden rule, this should be the latest script to run at boot. For a
-# developer snapshot, it is fine to set auto_recovery here. But for a stable
-# release, this script must in fact turn off auto_recovery.
-#
-# Why? Because the custom sysupgrade script for the device will turn on
-# auto_recovery to "yes". And it's the job of this script to set the
-# boot boot_count to 0 and then disable auto_recovery, as that condition
-# means that the stable release went well.
-#
-# I have to repeat: this script should be changed for stable releases.
-
-START=99
-boot() {
-	. /lib/functions.sh
-
-	case $(board_name) in
-		linksys,ea6350v3)
-			# make sure auto_recovery in uboot is always on
-			IS_AUTO_RECOVERY="$(fw_printenv -n auto_recovery)"
-			if [ "$IS_AUTO_RECOVERY" != "yes" ] ; then
-				fw_setenv auto_recovery yes
-				echo "Linksys EA6350v3: fw_setenv: auto_recovery has been set to yes"
-			fi
-			# reset the boot counter
-			fw_setenv boot_count 0
-			mtd resetbc s_env
-			echo "Linksys EA6350v3: boot counter has been reset"
-			echo "Linksys EA6350v3: boot_part=$(fw_printenv -n boot_part)"
-			;;
-	esac
-}

+ 43 - 18
target/linux/ipq40xx/base-files/lib/upgrade/linksys.sh

@@ -1,26 +1,51 @@
 linksys_get_target_firmware() {
+
+	local cur_boot_part mtd_ubi0
+
 	cur_boot_part=$(/usr/sbin/fw_printenv -n boot_part)
-	target_firmware=""
-	if [ "$cur_boot_part" = "1" ]; then
-		# current primary boot - update alt boot
-		target_firmware="alt_kernel"
-		fw_setenv boot_part 2
-		# In the Linksys EA6350v3, it is enough to set the boot_part as the boot command line is
-		# bootcmd=if test $boot_part = 1; then run bootpart1; else run bootpart2; fi
-		# - You probably want to use that if your device's uboot does not eval bootcmd
-		#fw_setenv bootcmd "run altnandboot"
-	elif [ "$cur_boot_part" = "2" ]; then
-		# current alt boot - update primary boot
-		target_firmware="kernel"
-		fw_setenv boot_part 1
-		#fw_setenv bootcmd "run nandboot"
+	if [ -z "${cur_boot_part}" ] ; then
+		mtd_ubi0=$(cat /sys/devices/virtual/ubi/ubi0/mtd_num)
+		case $(egrep "^mtd${mtd_ubi0}:" /proc/mtd | cut -d '"' -f 2) in
+		kernel|rootfs)
+			cur_boot_part=1
+			;;
+		alt_kernel|alt_rootfs)
+			cur_boot_part=2
+			;;
+		esac
+		>&2 printf "Current boot_part='%s' selected from ubi0/mtd_num='%s'" \
+			"${cur_boot_part}" "${mtd_ubi0}"
 	fi
 
-	# re-enable recovery so we get back if the new firmware is broken
-	fw_setenv auto_recovery yes
-	# see /etc/init.d/zlinksys_recovery
+	# OEM U-Boot for EA6350v3 and EA8300; bootcmd=
+	#  if test $auto_recovery = no;
+	#      then bootipq;
+	#  elif test $boot_part = 1;
+	#      then run bootpart1;
+	#      else run bootpart2;
+	#  fi
 
-	echo "$target_firmware"
+	case $cur_boot_part in
+	1)
+		fw_setenv -s - <<-EOF
+			boot_part 2
+			auto_recovery yes
+		EOF
+		printf "alt_kernel"
+		return
+		;;
+	2)
+		fw_setenv -s - <<-EOF
+			boot_part 1
+			auto_recovery yes
+		EOF
+		printf "kernel"
+		return
+		;;
+	*)
+		return
+		;;
+	esac
 }
 
 linksys_get_root_magic() {

+ 13 - 0
target/linux/ipq806x/base-files/etc/init.d/bootcount

@@ -0,0 +1,13 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+
+start() {
+	. /lib/functions.sh
+
+	case $(board_name) in
+	linksys,ea8500)
+		mtd resetbc s_env || true
+		;;
+	esac
+}

+ 0 - 19
target/linux/ipq806x/base-files/etc/init.d/linksys_recovery

@@ -1,19 +0,0 @@
-#!/bin/sh /etc/rc.common
-# Copyright (C) 2015 OpenWrt.org
-
-START=97
-boot() {
-. /lib/functions.sh
-
-case $(board_name) in
-	linksys,ea8500)
-		# make sure auto_recovery in uboot is always on
-		AUTO_RECOVERY_ENA="`fw_printenv -n auto_recovery`"
-		if [ "$AUTO_RECOVERY_ENA" != "yes" ] ; then
-			fw_setenv auto_recovery yes
-		fi
-		# reset the boot counter
-		mtd resetbc s_env
-		;;
-esac
-}

+ 38 - 19
target/linux/ipq806x/base-files/lib/upgrade/linksys.sh

@@ -3,28 +3,47 @@
 #
 
 linksys_get_target_firmware() {
-	cur_boot_part=`/usr/sbin/fw_printenv -n boot_part`
-	target_firmware=""
-	if [ "$cur_boot_part" = "1" ]
-	then
-		# current primary boot - update alt boot
-		target_firmware="kernel2"
-		fw_setenv boot_part 2
-		#In EA8500 bootcmd is always "bootipq", so don't change
-		#fw_setenv bootcmd "run altnandboot"
-	elif [ "$cur_boot_part" = "2" ]
-	then
-		# current alt boot - update primary boot
-		target_firmware="kernel1"
-		fw_setenv boot_part 1
-		#In EA8500 bootcmd is always "bootipq", so don't change
-		#fw_setenv bootcmd "run nandboot"
+
+	local cur_boot_part mtd_ubi0
+
+	cur_boot_part=$(/usr/sbin/fw_printenv -n boot_part)
+	if [ -z "${cur_boot_part}" ] ; then
+		mtd_ubi0=$(cat /sys/devices/virtual/ubi/ubi0/mtd_num)
+		case $(egrep ^mtd${mtd_ubi0}: /proc/mtd | cut -d '"' -f 2) in
+		kernel1|rootfs1)
+			cur_boot_part=1
+			;;
+		kernel2|rootfs2)
+			cur_boot_part=2
+			;;
+		esac
+		>&2 printf "Current boot_part='%s' selected from ubi0/mtd_num='%s'" \
+			"${cur_boot_part}" "${mtd_ubi0}"
 	fi
 
-	# re-enable recovery so we get back if the new firmware is broken
-	fw_setenv auto_recovery yes
+	cur_boot_part=`/usr/sbin/fw_printenv -n boot_part`
 
-	echo "$target_firmware"
+	case $cur_boot_part in
+	1)
+		fw_setenv -s - <<-EOF
+			boot_part 2
+			auto_recovery yes
+		EOF
+		printf "kernel2"
+		return
+		;;
+	2)
+		fw_setenv -s - <<-EOF
+			boot_part 1
+			auto_recovery yes
+		EOF
+		printf "kernel1"
+		return
+		;;
+	*)
+		return
+		;;
+	esac
 }
 
 linksys_get_root_magic() {

+ 14 - 0
target/linux/kirkwood/base-files/etc/init.d/bootcount

@@ -0,0 +1,14 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+
+start() {
+	. /lib/functions.sh
+
+	case $(board_name) in
+	linksys,audi|\
+	linksys,viper)
+		mtd resetbc s_env || true
+		;;
+	esac
+}

+ 0 - 19
target/linux/kirkwood/base-files/etc/init.d/linksys_recovery

@@ -1,19 +0,0 @@
-#!/bin/sh /etc/rc.common
-# Copyright (C) 2015 OpenWrt.org
-
-START=97
-boot() {
-. /lib/functions.sh
-
-case $(board_name) in
-	linksys,audi|linksys,viper)
-		# make sure auto_recovery in uboot is always on
-		AUTO_RECOVERY_ENA="`fw_printenv -n auto_recovery`"
-		if [ "$AUTO_RECOVERY_ENA" != "yes" ] ; then
-			fw_setenv auto_recovery yes
-		fi
-		# reset the boot counter
-		mtd resetbc s_env
-		;;
-esac
-}

+ 37 - 15
target/linux/kirkwood/base-files/lib/upgrade/linksys.sh

@@ -3,23 +3,45 @@
 #
 
 linksys_get_target_firmware() {
-	cur_boot_part=`/usr/sbin/fw_printenv -n boot_part`
-	target_firmware=""
-	if [ "$cur_boot_part" = "1" ]
-	then
-		# current primary boot - update alt boot
-		target_firmware="kernel2"
-		fw_setenv boot_part 2
-		fw_setenv bootcmd "run altnandboot"
-	elif [ "$cur_boot_part" = "2" ]
-	then
-		# current alt boot - update primary boot
-		target_firmware="kernel1"
-		fw_setenv boot_part 1
-		fw_setenv bootcmd "run nandboot"
+
+	local cur_boot_part mtd_ubi0
+
+	cur_boot_part=$(/usr/sbin/fw_printenv -n boot_part)
+	if [ -z "${cur_boot_part}" ] ; then
+		mtd_ubi0=$(cat /sys/devices/virtual/ubi/ubi0/mtd_num)
+		case $(egrep ^mtd${mtd_ubi0}: /proc/mtd | cut -d '"' -f 2) in
+		kernel|rootfs)
+			cur_boot_part=1
+			;;
+		alt_kernel|alt_rootfs)
+			cur_boot_part=2
+			;;
+		esac
+		>&2 printf "Current boot_part='%s' selected from ubi0/mtd_num='%s'" \
+			"${cur_boot_part}" "${mtd_ubi0}"
 	fi
 
-	echo "$target_firmware"
+	case $cur_boot_part in
+	1)
+		fw_setenv -s - <<-EOF
+			boot_part 2
+			bootcmd "run altnandboot"
+		EOF
+		printf "kernel2"
+		return
+		;;
+	2)
+		fw_setenv -s - <<-EOF
+			boot_part 1
+			bootcmd "run nandboot"
+		EOF
+		printf "kernel1"
+		return
+		;;
+	*)
+		return
+		;;
+	esac
 }
 
 linksys_get_root_magic() {

+ 18 - 0
target/linux/mvebu/base-files/etc/init.d/bootcount

@@ -0,0 +1,18 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+
+start() {
+	. /lib/functions.sh
+
+	case $(board_name) in
+	linksys,caiman |\
+	linksys,cobra |\
+	linksys,mamba |\
+	linksys,rango |\
+	linksys,shelby |\
+	linksys,venom)
+		mtd resetbc s_env || true
+		;;
+	esac
+}

+ 0 - 20
target/linux/mvebu/base-files/etc/init.d/linksys_recovery

@@ -1,20 +0,0 @@
-#!/bin/sh /etc/rc.common
-# Copyright (C) 2015-2016 OpenWrt.org
-# Copyright (C) 2016 LEDE-Project.org
-
-START=97
-boot() {
-. /lib/functions.sh
-
-case $(board_name) in
-	linksys,caiman|linksys,cobra|linksys,mamba|linksys,rango|linksys,shelby|linksys,venom)
-		# make sure auto_recovery in uboot is always on
-		AUTO_RECOVERY_ENA="`fw_printenv -n auto_recovery`"
-		if [ "$AUTO_RECOVERY_ENA" != "yes" ] ; then
-			fw_setenv auto_recovery yes
-		fi
-		# reset the boot counter
-		mtd resetbc s_env
-		;;
-esac
-}

+ 36 - 17
target/linux/mvebu/base-files/lib/upgrade/linksys.sh

@@ -3,26 +3,45 @@
 #
 
 linksys_get_target_firmware() {
+
+	local cur_boot_part mtd_ubi0
+
 	cur_boot_part=`/usr/sbin/fw_printenv -n boot_part`
-	target_firmware=""
-	if [ "$cur_boot_part" = "1" ]
-	then
-		# current primary boot - update alt boot
-		target_firmware="kernel2"
-		fw_setenv boot_part 2
-		fw_setenv bootcmd "run altnandboot"
-	elif [ "$cur_boot_part" = "2" ]
-	then
-		# current alt boot - update primary boot
-		target_firmware="kernel1"
-		fw_setenv boot_part 1
-		fw_setenv bootcmd "run nandboot"
+	if [ -z "${cur_boot_part}" ] ; then
+		mtd_ubi0=$(cat /sys/devices/virtual/ubi/ubi0/mtd_num)
+		case $(egrep ^mtd${mtd_ubi0}: /proc/mtd | cut -d '"' -f 2) in
+		kernel1|rootfs1)
+			cur_boot_part=1
+			;;
+		kernel2|rootfs2)
+			cur_boot_part=2
+			;;
+		esac
+		>&2 printf "Current boot_part='%s' selected from ubi0/mtd_num='%s'" \
+			"${cur_boot_part}" "${mtd_ubi0}"
 	fi
 
-	# re-enable recovery so we get back if the new firmware is broken
-	fw_setenv auto_recovery yes
-
-	echo "$target_firmware"
+	case $cur_boot_part in
+	1)
+		fw_setenv -s - <<-EOF
+			boot_part 2
+			bootcmd "run altnandboot"
+		EOF
+		printf "kernel2"
+		return
+		;;
+	2)
+		fw_setenv -s - <<-EOF
+			boot_part 1
+			bootcmd "run nandboot"
+		EOF
+		printf "kernel1"
+		return
+		;;
+	*)
+		return
+		;;
+	esac
 }
 
 linksys_get_root_magic() {