How I Revived an Nforce2 Mobo With a Bad Bios

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Switching BIOS chips – The Byter, aka Elior Zeno

It all started with me getting two mobos for reviewing, the EPOX 8RGA+ and the CHAINTECH 7NJS0 (both Nforce2 based). I started testing the 8RGA+ and at a certain point, it just stopped posting. Clearing the BIOS did not help – it just gave FF debug code on the port 80 display.

I gave up on it and hooked the 7NJS0; after playing with it a while, it gave the well known C1 debug code. After checking CHAINTECH site, I found out that the new BIOS takes care of that problem… but I can’t post in order to flash it… what can I do?

I gave up on this one too (for now).

My mobo is a EPOX 8RDA+. After playing around with it, water cooled and all, I wanted to get that VDD up a little, but I made a mistake with the pot and the board caught smoke and almost fire… dead mobo :

Me kill mobos – I can kill yours for free!

So what do I have by now? One 8RGA+ with bad BIOS (hangs at FF), one 7NJS0 with bad BIOS (hangs at C1), and one burned out 8RDA+ (but with a good BIOS).

My first thought was that all three of them are Nforce2 based, so their BIOS’s are much alike, and then I thought: “Why couldn’t I try the good BIOS from the burned out 8RDA+ in the 8RGA+?”

I did, it gave more than that FF, but it hung on C1…

Then I took that good BIOS and used it in the 7NJS0 mobo – IT POSTED!

Yes it did! All the magic health from the 8RDA+ BIOS gave a reading of 0, but it posted. I couldn’t really change any FSB settings and many other options, but I could boot from a CDROM and from my HD with Win XP Pro on it (installed on the 8RDA+).

After getting the latest BIOS for the 7NJS0 (the one that fixes the C1 hang), I booted from the CD into clean DOS and tried to flash the 8RDA+ chip with the 7NJS0 BIOS….

It didn’t work…

At start, it just said something about that the machine part number is wrong. After using some switches on AWDFLASH to overcome that, it gave me “file size too large” or something like that – the 8RDA+ BIOS is ~260K and the 7NJS0 is ~512K.

Now I was stuck – what more can I do to flash this chip with the BIOS I want? Maybe there is another answer than what I did, but let me tell you what I did.

I thought “Hey, the BIOS takes part only on post, so maybe when I’m in DOS (after post and boot), I can take it out (the BIOS chip) and leave the mobo still on and not locked up?!”

IT WORKED!

When in DOS, I took out the 8RDA+ chip, plugged in the 7NJS0 (C1 hang BIOS chip) and the mobo did not lock-up!

And then I just used AWDFLASH and flashed the 7NJS0 chip with the new BIOS – it worked and now all is good, I’m typing this article on this mobo 🙂

After this success I thought, “Maybe I can boot to DOS and then plug in the bad 8RGA+ BIOS (hang at FF) and flash it with the new 8RGA+ BIOS and revive another mobo by doing that.”

But when I tried it, it went OK till the screen in AWDFLASH that shows the blocks it writes, I didn’t do anything there … maybe the chip is bad…
I couldn’t flash the 8RGA+ BIOS on the 8RDA+ chip either – “file size too large”.

In conclusion, I would say to all you Overclockers out there, when you buy a mobo in order to overclock it, get a spare BIOS or two, or three, or more… and be sure to flash it with the newest good BIOS *before* overclocking
If you can get a BIOS recovery kit or something – DO IT, it can save you from an RMA.

Ed note: There is a neat little product that called Bios Savior that might fill the bill. Chet also found an interesting use for it HERE.

The Byter – aka Elior Zeno Israel

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