Thinkpad 755CX: cannot update BIOS without charged battery.

Don't ask how to hack password. (BIOS Passwords)
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Joined: Sun Jan 01, 2017 1:00 am

I need to update the BIOS on an old IBM Thinkpad 755CX. Without a BIOS update it won't recognize its Mwave modem/sound card under Windows98 (I'm making this into a retro gaming machine and need sound).

The latest revision of the BIOS is 1.44 and it's found in a file stype144.exe (can currently be found at ... tpe144.exe ) - it's a self-extracting disk image that writes a raw image directly to a floppy disk. Here's the contents of the floppy disk after extraction:

11/07/1996 02:33 PM 524,288 $0017000.FL1
11/14/1996 01:44 AM 7,408 COMMAND.COM
11/14/1996 01:44 AM 25 CONFIG.SYS
02/28/1992 12:00 PM 33,446 IBMBIO.COM
02/28/1992 12:00 PM 37,378 IBMDOS.COM
11/14/1996 01:44 AM 43,903 UPDTFLSH.EXE
11/14/1996 01:44 AM 12,501 USERINT.EXE
11/14/1996 01:44 AM 20,883 UTILINFO.EXE

The main flash program is updtflsh.exe; it however requires that the laptop is both plugged into a power supply, and have a fully charged battery - otherwise it refuses to work.

I don't have a working battery for this laptop (I have a few dead ones), and any attempts that I've made over the past few weeks to find one anywhere were unsuccessful. Considering that the laptop is 20+ years old, not surprising.

I have found on the internet methods for flashing the BIOS without a battery on Thinkpad laptops from a newer generation (770 and 600) but that required the creative use of a utility flash2.exe which is found on the BIOS update disks for those laptops. However the disk for the 755CX does not use flash2.exe.

At this point I have given up trying to find a battery. It seems that it's easier to find an unicorn than a working battery for Thinkpad 755CX. I need to find a method for flashing the BIOS without a battery.

Any ideas? If needed I can post a zipped file with the contents of the BIOS update disk. Actually I' going to try and attach it to this post.
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