I recently purchased a used Nokia N810. I was enjoying exploring its features when I decided to try to modify the logo that the bootloader displays when the device first powers on. I modified a couple of bytes in the NOLO secondary bootloader (filename secondary.bin-RX-44:0801,0802,0803,0804,0805,0806,0901,0902) that corresponded to NOKIA logo, and re-flashed the bootloader with the flasher-3.0 program.

Bad idea. The N810 no longer powers on at all. After searching the forum, I gathered that I would have to send the device to Nokia for a "cold flash". I shipped it to the Nokia service center and agreed to pay the $53 they wanted to perform a cold flash, considering it an expensive lesson learned to be more careful.

But now they've shipped the N810 back to me with a terse note that it is "BER" (beyond economical repair, I think) because it has "corrupt memory". I can't get any more details from them.

So after agonizing over buying the N810, it looks like I've ruined it without even modifying the hardware. Even if I somehow managed to access the JTAG connector behind the battery cover, which is probably beyond my expertise, my understanding is that it's disabled in software. Do you think there's any chance another repair shop could fix it? Should I just throw it away, or would it be worth anything to sell it for parts? Any other ideas? I'm at my wit's end.

Well, if the other parts are still in good shape, it'd definitely be worth selling for parts. The BER rating might have come about (given the corrupt memory diagnosis) due to failure of one of the flash chips. If that's the case, someone who's good enough with soldering stuff of that size may consider taking it on as a project and replacing the flash memory on the device, assuming that's all that's wrong.

If nothing else, that 4" touch screen is worth quite a bit still.

I had a problem reacently where one of my Nokias N810 would not Power on completly.I just went on and upgraded/reinstalled its OS...
After that it works fine...Of course i had to take the external Memory Card out and erase all its contents by formating it.And awryithing was back to Normal.

The port is not enabled for use in Maemo - by default - if the tablet is functioning normally. With the tablet b0rked, there's nothing to check to see if it's enabled so it should work. The flasher has a special option for cold flashing.

The bigger problem is finding a cable that works. Nokia do not sell them. But there have been threads here on cold-flashing but no-one has actually done it. But the threads contain useful information nevertheless. http://johannes.sipsolutions.net/N810 (the serial part) but I do not know if this is one and the same.