Yesterday my phone's screen changed to a black screen with the white Apple logo & a progress bar. I think it's the restore screen. I was actually on the phone at the time via bluetooth headset. The screen changed between that and the springboard (or lockscreen maybe, I can't remember, I was an important phone call). The screenchanges seemed to coincide with the progress bar's progress.

3GS Spirited from stock 3.1.3 old boot rom if that makes a difference.

Thanx for any info.