i have a very strange problem with Netgear R6220 and release 21.02.2. Anyone experienced this kind of problem with this router or any other, or with 21.02.x release?
The problem is that after reboot router gets reset to default config losing all the custom settings i set, e.g. ip address of router reverts back to default 192.168.1.1 alas i set to 192.168.1.2. while router is on I can setup everything i want (vlans, wifi etc) via luci or cli, all goes well, but the very moment i reboot am back to square one with all default configs.
as far as i know this hw has no dual boot partition.
That generally points at an issue with mounting the overlay (or you having installed an initramfs image instead of the proper one).
Before debugging this any further, I'd suggest to flash the sysupgrade image again (make a fresh download, same version or newer), without retaining settings(!). If that solves it, great - if not, we can still dig deeper.
that's really weird to be honest, as when from swconfig to dsa I did upgrade the only sensible way, i.e. to discard any old settings, and since I did minor dot release upgrades. So I would not expect this kind of solution but anyhow thank you very much @slh for the suggestion, it looks re-flashing fixed it.
just an idea: some kind of verification at the end of sysupgrade or at first boot after sysupgrade maybe would be beneficial to avoid situation like this (verify hash of critical files / directory?). As there was no sign / warning whatsoever indicating that sysupgrade had any problem. so if anything goes side ways during sysupgrade but the system can boot up maybe it can be detected and show some error messages.
when I had to cut power for other reason I was really surprised to find out my router reverted back to its defaults (which was not that straightforward root cause as i use this router as dumb ap, it was just a guess that this router is the problem as clients were not able to DNS resolve so probably something acting as alternative DNS resolver other than my main router and this faulty one was neither reachable through it's assigned IP address). Anyhow thanks again.
The overlay is formatted during first boot, if that fails, it will cry dire error messages into the syslog (logread) - you should also see failures to mount the overlay on each subsequent reboot in the syslog as well. There are no other, more obvious, ways to do this, on the one hand no-overlay is a normal mode of operations for the initramfs images (regularly used during development and sometimes for convoluted, two-stage installations on difficult devices) and to prevent bricking the device into hard-to-recover states, it can't just reject to boot up just because of a missing overlay either.