As a debian user, it's what I did 30mn after having bought my n800 lol.
I learnt very quickly how to reflash

I remember this nice long progressbar going till the end, hearing this nice nokia tunes and then .. nothing.. typical..


Among 10 upgraded packages there was 1 buggy (I think gtk) and this was clearly a problem in this package which was not aimed at scratchbox. I think you pull experimental stuffs. It may or may not work.. It's like russian roulette
The fact that the boot process is so picky and doesn't leave you to a shell is the problem.. but it's an internet tablet afterall.. I would really like to know if it's possible to boot in two stages:
arrive in a shell
launch the rest of the process. I'm not asking for kdm or startx simply a pause to a shell and then finish the bootup manually.