Yes, I searched this subject. I found only one direct reference to this problem very early in 07. No solution was arrived at at the time. I have no solution to it now nor do I expect that anyone else does either ( do tell if you do please). But I thought it might be worth noting for the record that I have not had this problem ever all this year until I just recently yanked it to the floor by tripping on the power cord. So I'm thinking maybe the problem is more hardware than software related. But I'm just guessing here.
So, the N800 reboots every few minutes while being charged. It does a full reboot if it has been turnd on. If it has not been turned on, then it boots to the white Nokia screen. It does not reboot while being run with battery power. This is with the 2007 OS

FWIW
NS