I tried to upgrade bios from my thinkpad 600 with instructions above, but no have success. But after various retry, I have success.
Describe below, steps I used to upgrade my thinkpad 600:
I tried upgrade without battery and no FDD.
Clear your HDD, or use other, but clear.
Format and install MS-DOS 7. MS-DOS 7 can be found in boot disk from Windows 98 or Windows Milleniun. I have used Windows Millenium.
Use a CLEAN boot disk, no autoexec.bat, no config.sys, no cdromdriver, etc.
Create a bootable CD, from floppy, to this use, UltraISO, Nero, etc...
I suggest use RW media, it's more practical.
To install, format with this command, without commas: "format c: /u /s" to standard format or use "format c: /q /s" to faster format.
Create dir on harddisk, ex: "Bios"
Copy to this directory, the following files:
These files can be found on upgrade bios archive, and can be downloaded, from IBM site. Create a diskette, and copy this files to CD-ROM, put in CD-ROM drive on Thinkpad, and copy to directory.
Now, go to "c:\bios" directory, and type "dir".
Look if files $0029000.fl1 and $0029000.fl2, appears as "_0029000.fl1" and "_0029000.fl2".
I don't know, because MS-DOS7 change the "$" character to "_".
Type following command:
rename _0029000.fl1 $0029000.fl1
rename _0029000.fl2 $0029000.fl2
Type "dir" again and check the correct file names.
Now, reboot and boot from harddisk, from MS-DOS7. Go to directory "Bios" and type:
And waiting to finish upgrade.
DO NOT DISCONNECT POWER until upgrade finish.
After finish, power off thinkpad, and power on again. Hold F1 down and go into Easy Setup under "Config" click on Initialize to ensure defaults and settings are no error.
Now, your thinkpad as upgraded! Reinstall your operating system or replace harddisk, if you have changed to other to upgrade.
This working 100% on my ThinkPad 600 (model 2645-21U) without battery and floppy disk.
But, I remind, do for its on your own and risk, I don't take the responsibility if you damage you thinkpad.
s by Fudeba, from Brazil.
p.s. sorry for my bad english (or "engrish"???) hehehe.