Windows 10: My screen shows no signal, when I change video mode from Legacy to Uefi

Hi, I want to enable secure boot and for that I have to disable CSM mode and to do that I have to change video mode from legacy to uefi, But the problem is when I change video mode from legacy to uefi and boot it my screen shows no signal and I have to take cmos battery out to reset the bios.Is there any solution?

:)

 

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.

 

UEFI vs Legacy boot mode

Yep, UEFI mode with Win 10 loading I get the Asus logo.

IIRC there maybe an option within motherboard UEFI to disable the Asus logo but not looked into it. On another forum I have read that what logo you get at Win 10 loading is the easiest way to know what bios mode OS is in.

If system is booting in legacy mode - you get Windows Logo.
If system is booting in UEFI mode - you get OEM logo.

Above also applies to Win 8 but not Win 7.

 

UEFI vs Legacy boot mode

I also recommend legacy mode. UEFI has to tight integration with the OS which is exactly the problem. There was a case where UEFI installed bloatware on fresh Windows installations automatically. It shouldn't be supposed to be able to do that unless the firmware was open-source.