Hello. I installed an amd firepro m4000 on a 2011 imac 21 inch. Specifically one from dell blue with bios chip onboard. I flashed the rom with M4000-enablegop.rom and installed the open core with the correct boot-args. radpg=15, agdpmode=pikera -wegtree. Windows working perfectly. In High Sierra black or very distorted screen. Do you think it could solve the problem on macOS? I know this particular card has sleep and wake problems on iMacs 2011, but I have no display at all.