I had an issue yesterday that had me flummoxed for a bit. I have a T22 laptop that I needed to flash the bios on. The battery was dead so the friendly folks at IBM had blocked me from being able to update as the battery was not charged. (because it won't hold a charge.) After several trial and errors with no luck, I stumbled on the Thinkpad 600 thread here and though i couldn't find anything that helped my situation, I realized that I'm not the only one with this problem.
I have found a solution and I thought I would share. I downloaded the update floppy and extracted it to a blank floppy disk. This automatically boots to the IBM Bios Update program using IBM Dos. Everything looks like it will work until it does the check of the battery and then blocks you from doing it. I tried booting up with a regular boot disk and sneaking in the back way using the QKFLASH.EXE but I was blocked again by a memory error.
My solution was to disable the executable that checks for the AC/Battery status,(UPDTFLSH.EXE) but that just caused the program to fail. So I tricked it into updating by copying the QKFLASH.EXE and renaming UPDTFLSH.EXE to UPDTFLSH.EXE.old and renaming the "Copy Of QKFLASH.EXE" to UPDTFLSH.EXE. Booted with the disk and though the screen is not as pretty as the original probably is, I was able to update the BIOS and went on my merry way.
Hopefully this helps someone get out of this sticky situation.