Hi all - to state my question quickly - I have a very highly modded EVGA 3090 FTW3 that's been converted to Hybrid cooling using their kit, along with other additions ill add below.  I can't seem to overwrite the KingPin bios I flashed to the STOCK Bios firmware setting with any other firmware via NVFlash.  I must be doing something wrong.
 
Problem Details:
I used NVFlash to update the STOCK BIOS setting firmware chip on my 3090 FTW3 Ultra to use the 520watt KingPin Bios.  It works, but due to EVGA allegedly F'ing EVGA owners, (and only EVGA owners) this Firmware is designed to NOT work perfectly on my GPU, where it DOES work perfectly on many other non-EVGA branded cards.  Thus the 500watt XOC Bios I have installed on my OC Firmware slot actually produces better OC results.  I want to remove the KP bios and install the 1000w 3090 FTW3 Ultra Bios.   
 
Every time I try to update/overwrte the bios, it tells me it's an invalid card for this firmware now.  I've tried to NVFlash it back to just the standard, non-o/c setting and it gives me that error.  I also can't update it with newer KingPin bios because it doesn't see itself as that GPU either for some reason, even though it registers as a KP.
 
I currently have the 500watt XOC Bios installed on the OC switch BIOS setting firmware chip, and it works amazingly well.  I am able to daily a max 2.16GHz oc with an average clock speed after full heat soak right at 2.1 GHz, with VRAM set to 10.2 GHz. 
 
Current GPU Mods:  It's been converted to EVGA's hybrid water cooling kit, all thermal pads and paste were fully replaced, front and back, with Fuji Poly thermal pads, and the entire enormous copper block is covered in 4g's of Grizzly Kryonaut Extreme.  I also put FujiPoly thermal pads on the outside exterior of the Backplate, and installed custom heatsinks on those strips, along with a large square FujiPoly pad on the exposed backside of the GPU, with a large custom heatsink on top.
 
Finally, I have a total of 6 Noctua iPPC PFC 3000 RPM server farm radiator fans dedicated to cooling it.  4 in Push/Pull on the 240mm radiator, 1 pulling air directly in from the back of the case onto the GPU backplate (Lian Li 011 Dynamic XL) and the final fan positioned inside the case on the GPU backplate, aimed directly at the heatsinks (and motherboard to maximize CPU VRM cooling as well. Needless to say, TEMPS ARE NOT A PROBLEM.  I run out of my 500 watts of Voltage WELL before temps even get anywhere close to 350 watt max on stock air cooling.
 
Anyway, I want to keep the normal 500watt Bios on my OC switch and replace the gimped KingPin bios with the 1000 watt bios available for my actual card, and can't seem to get it to overwrite the Kingpin bios already on it.  (Obviously, I'm well aware of all the precautions/dangers associated...) 
 
Any help would very much be appreciated!
 
Thanks all!
Ryan