...just adding more to this because of one thing.
Yes, iND-BIOS 5003 had the IGR bug where you can just hit Back + White and it shuts down, or Back + Black and it resets...no triggers required. (This -might- be only with some controllers, I haven't tested)
I've always used the 5004 beta (in the /beta folder on the main Usual Place), named iND-BiOS.Beta.Feb-11-05, which fixed that bug.
I remembered that there's that IGR problem because I had reflashed normal 5003 to play around with virtual dvdrom/.ISO mounting (the modchip kernel patcher
utility didn't seem to like the changes done in that ind-bios beta), and just started running into the whole Back + black/white thing when messing with certain emulators. :/