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Need help in flashing XFX HD 4850 1GB (HD-485X-ZNFC) card

Apr 24, 2011
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New Jersey, USA
System Name Custom PC
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Memory G.SKILL Sniper Series 16GB (2 x 8GB) DDR3 1866 F3-1866C9D-16GSR
Video Card(s) GigaByte AMD HD 7950 3GB GDDR5 (GV-R795WF3-3GD) Flashed as AMD R9-280 (GV-R928WF3OC-3GD)
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Hi everyone,

I found this website a couple of weeks ago and have been trying to flash my card's BIOS since then. The problem is that this card uses the ATi Mobility M98 chip but is sold as a regular HD 4850 card. I purchased this card on sale on newegg a few days ago to make a Crossfire setup using my other HD 4850 card (Gigabyte GV-R485OC-1GH). The other card is a factory overclocked version and the chip runs at 700 Mhz and the memory at 993 Mhz. This card's chip runs at the default 625 Mhz and the memory at 993 Mhz.

My goal is to flash this card using the BIOS of the other Gigabyte card (the ideal solution), if possible, or at least make some changes in the current BIOS.

I first extracted the BIOS of the XFX card using GPU-Z v0.5.3, but RBE v1.28 probably took this BIOS as corrupt. The exact message that I get is " Invalid file specified. Not an ATI BIOS? - Debug information: 'CheckValid' reported error. " The only button avaiable to click is the OK button. By the way I successfully uploaded this BIOS to the TechPowerUp server using GPU-Z, but I still don't see it there.

Next, I extracted the BIOS using ATi WinFlash v2.0.1.14 (attached here) and opened it with RBE. It instantly opened this one without any errors. After making sure that I now have a backup and everything was perfect, I went for the next step, flashing this card using the BIOS of the Gigabyte card!

When I tried to flash using RBE+WinFlash I got the checksum mismatch error. I then tried the 'Force flash' checkbox and received "ROM programming FAIL" error. It also said "Error occurred: Unknown! Invalid BIOS or adapter selected? If this error persists, try using WinFlash itself."

I then tried flashing using WinFlash and received a "SubsystemIDs mismatch" error.

I lost my hope of flashing the Gigabyte BIOS on this card and proceeded with editing the current BIOS using RBE. No matter what changes I make here, once I try to flash it, I get "Fail" error using WinFlash. Even if I make just one small change, I still get this error. I also tried the 'unlock' switch using command prompt but I still got the same error. Then just to check, I tried to flash the original BIOS of this card and received the "This version of VBIOS s already installed" message.

Finally, I tried to flash the edited BIOS file using RBE+WinFlash and received this warning "The BIOS P/Ns of the BIOS you would like to flash and the adapter you selected are different. Are you sure you would like to proceed?" Yes/No. I selected Yes and received the same error that I got the first time I used RBE+WinFlash "ROM programming FAIL" and "Error occurred. Unknown.......". Same goes for Force flash: same error as the first time!

I don't know what to do now as I have run out of ideas. I tried everything I could from the documentation on this website, but failed every time. What I have not tried so far are the DOS methods. The resons:
1. I am not comfortable because of my limited DOS knowledge and experience.
2. I don't have any hope, because I think the problem is somewhere else.

One thing that I did notice is that when I open the original BIOS file in RBE, the "Video card:" text field says the word "(unknown)". I don't know if it has something to do with the failure.

This is where you guys come in! I really need your help and advice, specially the developers of these applications. Please let me know if you require something else from me to understand/fix this issue.

Thanks in advance!


Feb 20, 2008
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Guide To Video Card BIOS Flashing

Check that link for better ideas on flashing, flashing from windows can be a bit riskier than in DOS. I tried editing the provided BIOS to do what you want, upped the core clocks to 700 from the 625, also hopefully made it know what kind of card it is. Keep the one you attached handy so if my modded one does not work, you can save the card by putting the stock BIOS back on.