got the same problem with a 470 nitro+, at least i send it back to amazon and got a refund for the card, try to do that, i did it and was fine (Even with the modified bios)
I did that last night, new one on the way by friday. My thought is the card was modded on the other position vswitch bios but worked on my current vswitch bios, after I modded that one I had no way to fix either of them, hence why I tried the 1+8, or either the card literally is a dead card.
What I have determined is now that I know all the functions on the card, I will test both vbios switch as normal rom and working, then make sure I am in performance mode that only gets the updated rom
To be honest i dont know why my card failed, i flashed the bios on performance mode, and never touched the switch, the card lights were on, but never detected on bios, it was running fine for 5 months along with 4 more, but at least amazon refund me 80% of the card and now the price is lower so i got a new one (samsung memory) from the refund i got