Cant flash RX480 Bios. GPU not able to mine after modded Bios.

Hello!
I just tried to flash my GPU bios for my RX480 for the first time. i used the Polaris Bios Modder to mod the bios first. After i tried that and fail i used my old backup and tried again with 2 other bios versions from 2 tutorials. They also wont work. After flashing the 1x gpu, my claymore miner wont use the rx480 and only uses my 3x1070´s. In MSI Afterburner i just see the one RX GPU like that:
http://imgur.com/a/W0jdS
To flash my bios i used ATIflash and also switched the bios button on the gpu to the hdmi port side. I also have 3 GTX1070 and one RX480 (2 more on the way). Any ideas why it wont work? I also use Windows.