I tried a hitachi 40 gb drive -- reboots after 15-30 minutes
fujitsu 80 gb drive -- same (sorry, I forgot to write down the models on them)
Tried Toshiba 120 gb drive (mk1234gax) -- drove around the city all day saterday, no reboots at all. Works perfectly !!! .................
Haven't had a chance to expand the music partition yet, just wanted to see if the drive will work with the unaltered z2bypassed image first.