Upgrading from Cambridge Fibre (ISP) firmware (OpenWRT fork?)

[bjames2011]

I'm trying to make sense of the installation process, but I'm finding it somewhat hard to follow for my router - it's a Belkin RT3200 which seems to be running a custom OpenWRT build.

I purchased the device second-hand on eBay with the intention of installing OpenWRT, but on first boot I'm greeted with a web UI that has "Cambridge Fibre" (a local ISP) branding.

The footer on the page indicates that it's an OpenWRT build (possibly customised in some way?):

[Powered by LuCI openwrt-22.03 branch (git-22.167.28394-8a4486a)](https://github.com/openwrt/luci) / OpenWrt 22.03.0-rc5 r19523-bfd070e7fa cfn1657187640

I'd like to install the latest stable build. Do I need to run the installer first or just upload the new firmware directly? I can't tell if the flash layout has been updated already, however, given the device is running 22.03.0, I presume it might not have been. If someone could summarise the installation steps, I would be grateful.

[bjames2011]

@dangowrt is this case supported by the installer? I'm hesitant to jump in and flash new firmware if it might brick the device.

[bjames2011]

Some more information about the device; it appears to have a UBI filesystem, but the block names don't match the information on the OpenWRT page for the router.

Login message

> ssh [email protected]
...

BusyBox v1.35.0 (2022-07-06 19:09:39 UTC) built-in shell (ash)

   ____                _          _     _              _____ _ _
  / ___|__ _ _ __ ___ | |__  _ __(_) __| | __ _  ___  |  ___(_) |__  _ __ ___
 | |   / _` | '_ ` _ \| '_ \| '__| |/ _` |/ _` |/ _ \ | |_  | | '_ \| '__/ _ \
 | |__| (_| | | | | | | |_) | |  | | (_| | (_| |  __/ |  _| | | |_) | | |  __/
  \____\__,_|_| |_| |_|_.__/|_|  |_|\__,_|\__, |\___| |_|   |_|_.__/|_|  \___|
                                          |___/       The Future is Light
 -----------------------------------------------------------------------------
 OpenWrt 22.03.0-rc5, r19523-bfd070e7fa
 -----------------------------------------------------------------------------
=== WARNING! =====================================
There is no root password defined on this device!
Use the "passwd" command to set up a new password
in order to prevent unauthorized SSH logins.
--------------------------------------------------

Mount points

root@38E10M3BA03123:/# mount
/dev/root on /rom type squashfs (ro,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,noatime)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,noatime)
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noatime)
/dev/ubi0_5 on /overlay type ubifs (rw,noatime,assert=read-only,ubi=0,vol=5)
overlayfs:/overlay on / type overlay (rw,noatime,lowerdir=/,upperdir=/overlay/upper,workdir=/overlay/work)
tmpfs on /dev type tmpfs (rw,nosuid,noexec,noatime,size=512k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,noatime,mode=600,ptmxmode=000)
debugfs on /sys/kernel/debug type debugfs (rw,noatime)
none on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,noatime,mode=700)
pstore on /sys/fs/pstore type pstore (rw,noatime)

Block devices

root@38E10M3BA03123:/# ls -1 /dev | grep -E 'mtd|ubi'
mtd0
mtd0ro
mtd1
mtd1ro
mtd2
mtd2ro
mtd3
mtd3ro
mtdblock0
mtdblock1
mtdblock2
mtdblock3
ubi0
ubi0_0
ubi0_1
ubi0_2
ubi0_3
ubi0_4
ubi0_5
ubi_ctrl
ubiblock0_4
ubiblock0_4p1

[bjames2011]

I've poked a little deeper and the flash (MTD/UBI) block layout is different from both the factory default and the OpenWRT layouts listed here.

Current MTD blocks

root@38E10M3BA03123:/# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00080000 00020000 "bl2"
mtd1: 00140000 00020000 "fip"
mtd2: 00100000 00020000 "factory"
mtd3: 07d00000 00020000 "ubi"

UBI info

root@38E10M3BA03123:/# ubinfo --all
UBI version:                    1
Count of UBI devices:           1
UBI control device major/minor: 10:63
Present UBI devices:            ubi0

ubi0
Volumes count:                           6
Logical eraseblock size:                 126976 bytes, 124.0 KiB
Total amount of logical eraseblocks:     1000 (126976000 bytes, 121.0 MiB)
Amount of available logical eraseblocks: 0 (0 bytes)
Maximum count of volumes                 128
Count of bad physical eraseblocks:       0
Count of reserved physical eraseblocks:  20
Current maximum erase counter value:     2
Minimum input/output unit size:          2048 bytes
Character device major/minor:            248:0
Present volumes:                         0, 1, 2, 3, 4, 5

Volume ID:   0 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        9 LEBs (1142784 bytes, 1.0 MiB)
State:       OK
Name:        ubootenv
Character device major/minor: 248:1
-----------------------------------
Volume ID:   1 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        9 LEBs (1142784 bytes, 1.0 MiB)
State:       OK
Name:        ubootenv2
Character device major/minor: 248:2
-----------------------------------
Volume ID:   2 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        72 LEBs (9142272 bytes, 8.7 MiB)
State:       OK
Name:        recovery
Character device major/minor: 248:3
-----------------------------------
Volume ID:   3 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        67 LEBs (8507392 bytes, 8.1 MiB)
State:       OK
Name:        boot_backup
Character device major/minor: 248:4
-----------------------------------
Volume ID:   4 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        260 LEBs (33013760 bytes, 31.4 MiB)
State:       OK
Name:        fit
Character device major/minor: 248:5
-----------------------------------
Volume ID:   5 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        559 LEBs (70979584 bytes, 67.6 MiB)
State:       OK
Name:        rootfs_data
Character device major/minor: 248:6

[bjames2011]

The flash layout in my last message matches that used in previous OpenWRT releases (e.g. 23.05.0 as found on the Wayback Machine) - before the fip and factory blocks were also moved to UBI.

I'm closer to figuring this out, but still confused by this comment on the installation page:

Users already running OpenWrt 23.05.x or older, or snapshots before 2024-02-15 also need to re-run the installer yet another time to move fip and factory partitions into UBI volumes before running snapshots after 2024-02-15 as well as upcoming releases. Upgrading to release 23.05.4 does NOT require that you re-run the installer.

Given the current flash layout, I suspect I do need to rerun the installer, despite the above text implying this is only required "...before running snapshots after 2024-02-15..." (n.b. the listed stable version for this router is 23.05.5 - presumably released before "2024-02-15").

[bjames2011]

Another (related) question is which version of OpenWRT to use; the installation page states 23.05.5, however the build installer script has a hard-coded reference to a newer version:

> cat build_installer.sh
...
	OPENWRT_RELEASE="24.10.0"

I'll see if the wiki has any discussion on this...

Aside: The installation page could do with being tidied up a bit. I'm sure it makes sense if you're familiar with the device, but it's a bit hard to follow in a few places otherwise.

[bjames2011]

I used these in the end (v1.1.4/24.10.0):

• openwrt-24.10.0-mediatek-mt7622-linksys_e8450-ubi-initramfs-recovery-installer.itb
• openwrt-24.10.0-mediatek-mt7622-linksys_e8450-ubi-squashfs-sysupgrade.itb

...and followed these instructions (electing not to keep settings and forcing writing of the installer image).

After setting up the wifi interfaces, setting passwords, etc., there was still an issue connecting to the WAN, but this turned out to be an annoying restriction my ISP (Sky) uses to try and prevent third-party routers (by using DHCP client ID and vendor ID); the work-around for this is:

ssh [email protected]
...
> uci set network.wan.clientid='7573657240736b7964736c7c70617373776f7264'
> uci set network.wan.vendorid='SKY120'
> uci commit network
> service network restart

...alternatively, setting the same settings via the web UI: Network | Interfaces | wan | Advanced Settings