I've tried quite a few times to install Win10 with EFI boot and failed miserably with the following error That was until Squuiid told me that one of my PCIe cards has BIOS. So I removed my MSI R9 280X (the only PCIE cards in my Mac), put back GT120 and I installed Win10 EFI with no problems. I could even install it with R9 280X in place as long as I used GT120 as my display card. But once I installed the drivers (for both cards) I couldn't boot into it anymore. So, since then I have tried flashed bios and original UEFI ready bios in my R9 280X and results were the same (blue screen above), Im wondering what card are you using with Win10 EFI? Are all R9 280(X) problematic, or did I just do something with my ROMs when flashing them for boot screens? So, to repeat the subject What GPU are you using with your EFI installed Windows on MP4,1/5,1?