Well, unfortunately I found out a simple way to brick the N800.

This applies to all the Nokia tablets - if while in root you (stupidly) write to /dev/mtdblock0 (and likely mtdblock1-3, too!) you will overwrite the boot loader and brick the device.

It seems like I accidentally did this (I can't fully be certain that was the cause since the tablet won't boot) when attempting to mount a jffs2 image. I think I might have accidentally transposed /dev/mtdblock0 for /tmp/mtdblock0. ( It might be a good idea for someone to change the Maemo wiki so that someone else doesn't also stupidly do that. I would also recommend using a script if you're going to try a jffs loop on the tablet - and checking it to make ceratin it's correct about 5 times before executing it! )

So now I have a nice N800 paperweight.

It can only be recovered with a serial cold flash, if at all. . . Why is it, that after a couple of years now, no one has posted anything on how to do a cold flash? Is it REALLY that difficult? Or is it that there are really that few tablet owners? I've done plenty of JTAG flashes on WRT routers and it's not that hard. So why is it that there is nothing here on serial/jtag stuff?

In the meantime I went ahead and ordered another N800 since Nokia seems notoriously slow in fixing broken tablets. . .

Since I don't think I can kill the dead one any further I'm going to work on making up a serial cable to cold flash the thing. The Maemo wiki has a little info on that, but since there is nothing substantial I have the feeling there has been little success. . .

If anyone has any suggestions besides sending the tablet to Nokia I would greatly appreciate it!

I remember seeing the pinout somewhere or another. I think it's as simple as running the flasher in cold-flash mode once you get the cable built.

Well, that's a worse story than what I went through today.

I only had a severe lockup that trashed my filesystem. I'm trying an ext3 instead of an ext2 this time.

I hope you can get yours working again.

Pinouts I think are on this page:

http://maemo.org/community/wiki/Flasher_tool_usage

I hope. . .

I've seen the serial pinout on the Maemo site. The problem with making a cable is it requires a level translator IC since the levels on the Nokia are 3.3V when standard RS-232 is 12V. The site has links, but they refer to other devices, not Nokia tablets. . .

I would have thought by now that someone would have made a cable and could comment on whether it actually worked and what components they used. . .

I hate being the innovator on something like this since it's very easy to connect to the wrong pin and fry something permanently. At least the thing is already dead, so it would be no big loss.

Sorry to hear of your problems. From what I understand, however, ext3 is probably not a very good idea with embedded stuff like the tablet. The journal needs constant writes which will severely reduce the life of the flash memory. If it was me I would stick with ext2 and find the cause of the crash. . . and keep good backups.

I'm rather fortunate in that I have multiple recent backups of everything . . . unless the server they are stored on dies

I think a couple people on #maemo have done it. Might be worth your time to pop in and hang around for a few days to see if you can scare something up (I don't remember off-hand who and am too lazy to dig through the logs—maybe check for "jtag" here).

Ok, I'm most likely reaching here but one of the options in the Linux flasher utility is -c fo r cold flash I wonder if something like ./flasher-3.0-static -F RX............... -c -R (instead of the normal -f -R at the end) wouldn't help. Worse case... it does nothing. I've not tried I don't know.... ymWv (your millage WILL vary)

Only /dev/mtd0 (bootloader) and /dev/mtd1 (config partition) are critical. Others can be reflashed via USB flasher. Good we have confirmed this may happen :-) But still, are you sure? I was wondering if they are protected or not but never tried. On 770 even kernel partition was protected but on N800 it is not. I still hoped at least bootloader (mtd0) is protected since there is no reason to write there from linux. mtd1 is unprotected since some system tools need to write there.

Anyway I would suggest to search maemo-developers list (but I'm afraid you may not find answer) and post your problem there. Maybe some @nokia.com people will help.

I'm just wondering... seen all OS stuff is loaded on the internal SD card, can't you simply make a copy (aka ghost or dd ) of a working SD card and dump it on your SD?

Or is there a other catch?

edit: forget it... internal flash memory... doh...

So far it looks like they are NOT protected in any way. I suppose we can take that as a "Good Thing"™, unless of course you accidentally write to it.

Even though the tablet is bricked I can pretty much confirm that's what did it. The only other thing I did after attempting to mount a jffs file was to reboot to the MMC. Since that's been done a million times before we know that wasn't it. I then got a WSOD (White Screen of Death) and had to pull the battery to get it to power off. Now it's bricked. . .

If I can get a cable to get the thing working I'd be happy try try to brick it again, using the same (fscked up!) procedure

On another thought:

I was thinking this before, but polossatik got me posting it here now. If you can write to /dev/mtdblock0 then you can certainly also copy it via dd.. . . but then again it's already in the FIASCO image isn't it? That makes it even easier. . . Then somebody can take it and work on disassembling the boot loader stuff so that eventually there will be an OSS version of it, or at least a detailed description of EXACTLY what it does.

A disassembly and outline of the bootloader is badly needed and could come in quite handy! Unfortunately right now I need to work on a cable first!