You may need to do a forced flash, AFAIK there is a switch you can add to the nvflash command to ignore safety checks. Not sure if it is possible on newer GPUs, had to do it on 465->470 cards a few times.
Also, if drivers are not loading, you likely need to use the DOS version of nvflash on a DOS bootable USB stick.
HP-UX. I came, I saw, I was sad it would not run on my X86 box.