Hot flashing isn't so bad, but you need to know what you're doing.
Prerequesites:
- a board that works, works with Uniflash (1.40) and physically and logically fits the EEPROM chip you want to flash.
- a spare EEPROM of the correct size (until you're sure the BIOS is the problem and you have a working one, you don't want to risk destroying the original one)
- an absolutely minimal DOS system to boot into, just MSDOS.SYS, IO.SYS, COMMAND.COM, UNIFLASH.EXE and the image you want to flash is enough - and make sure it's on a reliable medium (not a floppy).
- some way of getting the EEPROM off the board. You have special extraction tools, but a sturdy knife or similar can suffice.
The only tricky bit is finding a board that will happily hot flash. In my experience, post 1998 Asus and MSI boards don't like to, but most low-end boards (PC Chips & co) do it fine, and so do Tyans. I used a Tyan Tsunami ATX S1846 for the last few BIOSs I needed to do.
Preparation:
- with the working board powered down, remove its BIOS EEPROM and very gently pat it into place in the socket. CHECK ORIENTATION WHEN YOU DO THIS. The idea is it can be removed with minimal effort and risk after booting.
Then the actual work:
- boot the board with its own BIOS.
- when you have a DOS prompt, remove the board's own BIOS and gently pat the new EEPROM into place. CHECK ORIENTATION WHEN YOU DO THIS.
- uniflash -e FILENAME.BIN
- power down the system, remove the new EEPROM and put it in its recipient board. CHECK ORENTATION WHEN YOU DO THIS.
- replace the original BIOS EEPROM in the flashing board. CHECK ORIENTATION WHEN YOU DO THIS.
That's all there is to it. All that can go wrong is short-circuiting something, potentially frying the hardware or yourself (although to do so with max 12V is challenging). Or putting the EEPROM in the wrong way. I emphasize that because in 15-odd years of hot flashing the only way I ever killed a board was putting the EEPROM in the wrong way round. When it was powered down, not even when it was on. It just caused a lot of magic smoke to escape when it was later turned on...
Given that (n=1) I feel that risk much greater than the rest of the hot flash procedure, I'm not so concerned about the difference between hot flashing and using an EEPROM programmer. You won't short anything with a running board with the latter, but you can just as easily fry it all if you put it in the wrong way round.
