Unbricking A Bricked Sapphire RX 6800 XT Nitro+?

I got a Sapphire RX 6800 XT Nitro+ off ebay that was (supposedly) working. However when I plugged it in, no video output. I ran my iGPU so I could get video output, and Device Manager does indeed recognize the 6800 XT but gives a code 43 error. I've flashed RX 5700/5700 XT BIOSes before, so I'm familiar with the whole process - I expect what happened is the seller tried flashing this card without knowing what he was doing, bricked it, and couldn't figure out how to fix it so he sold it. I know eBay will let me return it with no hassle, but I've been wanting a 6800/XT for a while now and I'd like to try fixing it before I have to deal with a return.


Things I've tried:

• The Code 43 error (can) show up when you've flashed an unsigned BIOS onto a card, and can be patched with the AMD ATI Pixel Clock Patcher. I tried ran the patcher, but the error remained.


• After saving the current BIOS (not that it's working anyway), I downloaded the Sapphire RX 6800 XT Nitro+ BIOSes from the TechPowerUp database and tried flashing those. The file hashes were identical to the BIOS on the card already, but I flashed it anyway. Still got the error.


• Also tried flashing the reference AMD RX 6800 XT BIOS as a last resort, but the current version of AMD VbFlash, v3.20, barfs out an SSID mismatch error and you cannot force it to flash anyway. Older versions with the modifications from Igor's Lab, AMD VbFlash v2.93+ and v3.04+, which *are* able to ignore those errors and flash anyway, do not recognize the RX 6000 series and therefore cannot flash a BIOS on them.

So, I'm at a bit of a loss. I'm 98% positive this card is just firmware bricked, not a hardware issue (otherwise Device Manager probably wouldn't be able to recognize the card at all), and because of that it should be possible to fix. But, I'm not sure how.


Any ideas?