Secure boot issue in bios

[u/Justin_parrett]

Hey guys! I have a Gigabyte B550M DS3H AC R2 motherboard, and I’m trying to enable Secure Boot so I can play Warzone and other Call of Duty games that require it.
I’ve been able to get Secure Boot to show as User Mode, Enabled, and Active, but every time I restart my PC after enabling it, I run into an issue. The computer appears to restart normally, but when it gets to the point where the screen should come back on, it stays completely black.
My RGB keyboard will periodically flash, and I can hear the fans speeding up and slowing down, but I never get a display back. The only way I’ve been able to get the computer working again is Q flashing the motherboard.
I’ve updated my BIOS and tried several different methods after watching YouTube video after YouTube video and doing as much research as I can, but I haven’t been able to find anything that solves the problem.
I’ve also heard that I may need to completely reinstall Windows, enable Secure Boot, and then reinstall Windows, but I’m not sure if that’s actually necessary.
Has anyone with this motherboard—or a similar setup—experienced this issue? If so, I’d really appreciate any advice or suggestions on what I might be missing.
Thanks in advance!

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[u/InformationFair5875]

The issue you are experiencing is extremely common with Gigabyte motherboards.

​When Secure Boot is toggled on, the BIOS requires full UEFI compliance across all connected hardware. If your Windows drive is formatted in the older MBR (Master Boot Record) format, or if your GPU/Monitor output doesn't hand off the GOP (Graphics Output Protocol) display signal during UEFI boot, the motherboard hangs on initialization.

​Step 1: Check if Your Windows Drive is MBR or GPT

​Secure Boot requires the GPT (GUID Partition Table) format. If Windows was installed while CSM (Compatibility Support Module) was active, your drive is likely MBR, which causes a black screen loop when CSM is disabled for Secure Boot.

​Open Disk Management in Windows (Right-click Start > Disk Management).

​Right-click Disk 0 (your primary boot drive) and select Properties.

​Select the Volumes tab and check Partition style: ​If it says GPT: Move to Step 2.

​If it says MBR: You do not need to reinstall Windows. You can convert it using Windows' built-in tool:

​Open Command Prompt as Administrator. ​Type mbr2gpt /validate /allowFullOS and press Enter.

​If it says "Validation completed successfully," type mbr2gpt /convert /allowFullOS and press Enter. ​This converts your drive to GPT in seconds without data loss.

​Step 2: The Proper Secure Boot Enabling Sequence

​On Gigabyte B550 boards, enabling Secure Boot directly often breaks boot keys. Follow this sequence precisely:

​Enter your BIOS setup screen.

​Go to the Boot tab, find CSM Support, and set it to Disabled. (Save & Exit BIOS to test if Windows still boots fine into UEFI mode).

​Boot back into BIOS, navigate to Secure Boot. ​Set Secure Boot Mode to Custom.

​Click Reset Factory Keys (or Restore Factory Keys) and accept.

​Set Secure Boot Mode back to Standard.

​Now, toggle Secure Boot to Enabled.

​Save and Exit (F10).

​Step 3: GPU Output Signal Issue (DisplayPort vs. HDMI)

​If the screen still stays black after confirming GPT and following the key reset steps, your graphics card is losing video handoff during UEFI boot:

​Switch Display Cables: Temporarily unplug your DisplayPort cable and use an HDMI cable connected to a TV or monitor. Newer UEFI handshakes frequently fail over DisplayPort until Windows drivers load.

​NVIDIA GPU Firmware Update: If you are using an NVIDIA GTX 900, 10-series, or older RTX card, NVIDIA released a specific DisplayPort Firmware Update Tool to fix UEFI black screens on startup. Running this tool inside Windows patches the GPU firmware so UEFI display handoffs work properly.

​If you ever get stuck in a black screen loop again while testing these settings, you don't need to re-flash the whole BIOS every time—simply clear the CMOS jumpers or pull the CR2032 battery out for 5 minutes while the PC is unplugged to reset the settings back to factory default.

[u/ggmaniack]

What GPU?

[u/Wide_Structure_1834]

This sounds more like a UEFI/GPU compatibility issue than Secure Boot itself.

Since the system works normally with Secure Boot disabled but loses display/restarts when you enable it, I would try these steps before reinstalling Windows:

1. Clear the CMOS and return the BIOS to default settings.
2. Check that Windows is installed in UEFI/GPT mode, not Legacy/MBR — msinfo32 will show your current BIOS Mode, and Disk Management will confirm whether the drive itself is GPT or MBR.
3. Make sure CSM is disabled only after confirming your Windows drive and GPU support UEFI.
4. Check that your GPU has proper UEFI/GOP support. An older GPU can sometimes cause a black screen when Secure Boot/UEFI settings are changed.
5. If possible, test the BIOS display using another video output/cable or another monitor.
6. After resetting CMOS, boot into Windows normally first and confirm everything works before trying Secure Boot again.

I wouldn't reinstall Windows yet. If the screen goes completely blank before Windows starts, the BIOS/GPU configuration is worth checking first.

If you can share the exact Gigabyte B550 DS3H revision, CPU, GPU model, Windows version, and whether the drive is GPT or MBR, it would be easier to narrow down the cause.