Windows 10: PC won’t boot in UEFI, only in CSM/legacy

Hello!I want to install a game that requires for me to enable secure boot, which also requires for me to switch from CSM to UEFI, but doing so will either BSOD or take me to automatic repair. The system works just fine in CSM and the disc is GPT.

:)

 

UEFI install vs legacy install

I don't think I can enable CSM for my motherboard without running into errors eventually, it just does not seem to like having uefi with csm on strangely. So everything went smoothly for your uefi install with CSM? By now I would thought uefi and uefi drivers would be the default option and legacy bios have its death but it does not seem like it.

Edit : Is this shown Uefi on your windows?

 

UEFI install vs legacy install

My machine won't boot via UEFI if CSM isn't enabled or if UEFI is forced for all devices. In particular, my storage controllers aren't supported strictly through UEFI so, for me, I will use UEFI and GPT disks however, I do still have CSM enabled with a preference for UEFI init over legacy init. It seems to work okay for me, even back on Windows 7.

 

Quick UEFI/Legacy question

I have had Hawaii cards and Fiji cards with UEFI roms, used 1 at a time on an Asus P5K Premium motherboard LGA 775 with Q6600 without an issue. AMD ROMs are Hybrid ROMs ie have a legacy section with UEFI module, so you won't have an issue with card which has UEFI ROM on legacy system. The legacy sytem will just ignore the UEFI module in vbios.

To make Windows show UEFI as bios mode you need your Z97 Pro Gamer in "Pure UEFI" mode (ie CSM = OFF). Windows IIRC only changes between legacy / UEFI on install, so even if you change to CSM=Off it may not show UEFI bios mode in Windows system info tool. I have not had 2 GPUs in a system at one time, even if I had them, I thought my PSU was not up to the job, so can not comment if only the primary display card requires UEFI module and it is irrelevant if secondary GPU does not.

If you get black screen/issue after setting CSM off then remove the card with legacy ROM, if mobo boots then you'll know you need to update the ROM on that card.