Netgear WAC510 repair “can’t create ‘/var/config’: No space left on device”

[jbriddle]

Hello. I recently purchased a used Netgear WAC510 AP with a boot problem. I opened up the AP and connected the UART header to a PL-2303HX TTL-USB adapter. Now I can interface with ipq40xx and SDK as root.

I grabbed the bootlog from the WAC510 and compared it to the OEM bootlog (see link and diff output, below).

I think I can see what the problem is: I get a “cp: can't create '/var/config': No space left on device” error which leads to a slew of “No such file or directory” errors.

So I checked the available space:

[root@SDK ~]# df -a
Filesystem                Size      Used Available Use% Mounted on
mtd:ubi_rootfs           24.5M     24.5M         0 100% /
proc                         0         0         0   0% /proc
tmpfs                   120.9M    100.0K    120.8M   0% /tmp
devpts                       0         0         0   0% /dev/pts
none                    120.9M      2.4M    118.5M   2% /etc
none                         0         0         0   0% /sys
/dev/mtdblock11          15.0M     14.8M    248.0K  98% /var

/var is 98% full! I don't know what went wrong. But I’d like to try and clear the memory and attempt a clean boot to factory condition and hopefully sidestep having to flash new firmware over TFTP. But I don’t know what commands to use to wipe the memory. Can anyone point me in the right direction? Thank you!

• Netgear WAC510 specs, OEM firmware, UART pinouts, OEM bootlog: https://openwrt.org/toh/netgear/wac510
• Here is the output of a 'diff -aw bootlog0.txt bootlog1.txt' command comparing bootlog0 (OEM) to bootlog1 (mine): https://pastebin.com/31nEy6hu
• My full bootlog with all errors: https://pastebin.com/hA0NbJ5t

[schumaku]

This /dev/mtdblock11 is a read-only ready to run file system which will be mounted as part of the boot process as a read-to-run read-only file system eg. ext2 . User data is located in a different mount point AFAIK as a part of a ram-disk mounted runtime.

[jbriddle]

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@schumaku wrote:

This /dev/mtdblock11 is a read-only ready to run file system which will be mounted as part of the boot process as a read-to-run read-only file system eg. ext2

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Gotcha. So no wiping that memory. I'm still confused how the "No space left on device" error happened in the first place. It seems like the solution would be emptying some corrupted memory....but I'm grasping at straws.

I tried following this tutorial to flash the OEM firmware (9.7.0.6) from my Mac terminal to the WAC510 over UART and TFTP but the power light on my AP never started flashing amber as the instructions stated. I did induce a flashing amber power light by hard-resetting it but it still didn't work. I'll try the same process on my Windows machine (method 1, method 2) and maybe it'll work.

Is there anything else I should try?

Happy new Year!