One year ago my nokia 770 went WSOD too...http://talk.maemo.org/images/smilies/confused.gif
Im currently about to use the serial connection of the N770. If you open the battery box you see the golden pins. So you have GND, RX and TX. The signal is not inverted and about 3,3V. I connected them to a FTDI USB Adapter and I can read the debug-output during bootup @115000 kbaud which stops at on point.
The problem is that the serial output from the terminal is not activated in
the firmwares of OS2007 or whatever else i tried. So extracted the filesystem with ./flasher and mountes it my Linuxlaptop.
somewhere in /etc/init.d it has to be activated -
Then you should have full access to the device.
Or by setting up a bluetooth serial connection it could be wireless.
Has someone of you has gone that way.