Today i wanted to try something new on my OpenWRT router… And while meddling with files by accident i corrupted network settings. I was unable to access it neither through LUCI, nor even SSH. I quickly found DHCP must have not been working, but even manually configuring network card did not helped. What to do?
Fortunately OpenWRT has Failsafe Mode. To get to i I had to reset my router with power button, wait some time until power LED started to blink 5 times a second, then press one of the buttons on it’s back and then LED started blinking even faster informing about Failsafe Mode enabled.
Then I had to connect my PC to eht0 interface (it was connected to second port, so I just switched cables), configure it’s IP manually and I was able to finally get to it with SSH and WinSCP.
Unfortunately it was not end of problems. I’ve tried hard- and soft-resetting it, but was unable to.
root@ (none):~# firstboot
root@ (none):~# umount /overlay && jffs2reset && rebootNeither of those commands worked, after either of them I’ve got:
/dev/ubi0_1 is not mounted
/dev/ubi0_1 will be erased on next mountBut after reboot issue was still the same. I’ve tried using
mount_rootBut this forced router to read network configuration from corrupted file and it was inaccessible again.
In the end I downloaded upgrade image for my router from https://openwrt.org/toh/netgear/netgear_r6220 and flashed it in Failsafe Mode, for that I copied image to /tmp using WinSCP and installed it
sysupgrade -n /tmp/openwrt.binFinally after that everything started to work and I had clean OpenWRT installation on my router.
Then the second part – getting everything to work again.
Fortunately before I’ve started meddling around guts of my router I made backup of configuration using LUCI System -> Backup / Flash Firmware -> Generate archive. Now I was able to just use option “Upload archive…” to get all configuration files back.
Bigger problem was packages – I copied /overlay to my PC, but unfortunately I did that just with plan copy/paste in WinSCP, pasting it back just didn’t worked. In the end I just used ‘/overlay/upper/usr/lib/opkg/status’ as guide which packages to install (and which not used ones to ignore).
Now reboot, and… Everything seems to be working fine. Uff. If I would need to configure everything form scratch… 🙂
In the end I backed up config again and backed up also /overlay this time using:
tar -cvzf /tmp/overlay.tar.gz /overlayAnd copied resulting file to my PC for safekeeping, where it is backed up multiple ways. In case if I would need to restore I can do it with:
cd /; tar -xvzf /tmp/overlay.tar.gzWe all learn by our mistakes, so now I’d be more cautious. And also maybe it would be good idea to buy second same device for experimenting…