Don't worry and don't be afraid, I've experienced it before. I also use rx 580 and flashing it with wrong bios and i fixed it. You can search at google " flashing bios rx580 1+8 pin method" , and remember to boot using gpu you want to flash (not iGPU) and you must use cmd dos to run flashing, do not use gui. And most importan thing, you must have rx580 8gb hynix original rom bios, if you don't have it, you can check at : anorak.tech