J7 not able to connect after disassembly

Hey folks!

I have a Roomba J7 that I can’t get to connect after disassembling to mod the cliff sensors - have tried factory resetting/adding as a new product and it gets to ‘verifying password’ then fails out with error BF0B06.

Everything appears ok otherwise - running a manual clean seems to work fine and I can see the hotspot it generates, but I can’t seem to set it up.

Have I fried something? Is there anything obvious I should check before I order a new motherboard?

Related: anyone have a good source for replacement boards for these guys? I can see a couple on eBay, but I’m not completely sold on the ‘genuineness’ of those.