Have I bricked my Ubiquity UniFi 6 LR?

[rwrjr]

While following these install instructions: https://openwrt.org/toh/ubiquiti/unifi_6_lr I missed a critical part of the command below

$ dd if=/dev/zero bs=1 count=1 of=/dev/mtdblock6

I accidentally left out the "count=1" option and instead of writing just one record it wrote 64k records. I'm sure this can't be good.

I am still connected via my PC and have an active ssh open. Can I recover?

[altuntepe]

no problem, reinstall stock firmware with tftp. redo the process from the beginning.

[rwrjr]

Shoot I was hoping somebody could dd /dev/mntblock6 to a file and send it to me. The author of the install instructions makes it sound like it's easy to break the case trying to get it open.

[bmork]

Don't have an LR so I don't know for sure. But the original contents is most likely the same as many other Unifi devices: a 32bit integer with values 0 or 1 telling the bootloader which kernel to boot, followed by the magic value 0x2be84da3. The rest is empty. One problem is that the endianness of the magic varies. This is a Unifi AP AC Pro:

root@unifiac2:~#  hexdump -C /dev/mtd7ro
00000000  00 00 00 00 a3 4d e8 2b  00 00 00 00 00 00 00 00  |.....M.+........|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00020000

This is a Unifi 6 Lite:

root@u6-1:~# hexdump -C /dev/mtd4ro
00000000  00 00 00 00 2b e8 4d a3  ff ff ff ff ff ff ff ff  |....+.M.........|
00000010  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*
00010000

I am guessing that the system will boot fine with the error you did, but I cannot guarantee that and I do think you're wise waiting instead of gambling...

But for the next time: Don't skip the backup step. Doing a mistake/typo like this during first-time install happens all the time. Having backups is important. OK, I know that doesn't help you now. Just stating it here for the next person reading this thread.

[rwrjr]

@bmork, thank you so much for the information you provided. Before I saw your reply I had gone through the trouble of removing the cover. Once inside I saw further disassembly was necessary to expose the serial pins, at which point I saw your reply.

Since I was still connected (yeah I know stupid removing the cover while it was powered up but I was careful) I decided to try to fix mtdblock6 using the data from your Unifi 6 Lite. I created an 8 byte file and wrote that to mtdblock6, being careful to set the bs and count parameters properly this time.

After a reboot I'm happy to say I'm now running OpenWRT on the 6 LR.