Title:
ASRock B850 Pro-A won't fully power off after shutdown (works normally otherwise) – BIOS test rules out Windows

Hi everyone,

I'm hoping someone can help me diagnose a really strange issue.

System

• Motherboard: ASRock B850 Pro-A
• CPU: AMD Ryzen 5 7600X (using integrated graphics)
• GPU: None
• PSU: MSI MAG A650BN
• Windows: Windows 11 Pro 25H2 (Build 26200.8737)
• BIOS: 3.20 (dated 21 Feb 2025)

The PC is about 7 months old and has been working perfectly until recently.

The problem

When I click Shut Down in Windows:

• The monitor immediately loses signal.
• The keyboard LEDs (Caps Lock / Num Lock) lose power.
• Windows appears to shut down completely.
• However, the CPU cooler, case fans, and motherboard remain powered indefinitely.
• The motherboard debug LEDs (VGA and BOOT) remain lit.

The PC never reaches a fully powered-off state.

The weird part

If I enter the BIOS and press the physical power button on the case, I get exactly the same behavior:

• Display turns off.
• Fans continue spinning forever.
• CPU cooler continues running.
• Debug LEDs remain lit.

Since it also happens directly from the BIOS, I don't think Windows is causing it.

Things I've already tried

• Disabled Fast Startup.
• Ran:shutdown /s /f /t 0
• Reinstalled the latest AMD chipset driver.
• Verified Windows power settings.
• Ran:powercfg /energy powercfg /a
• Restart works perfectly every single time.
• Booting into Windows is completely normal.
• The PC is stable under load with no crashes.
• No dedicated GPU is installed.
• BIOS ACPI settings appear normal.
• USB power in S5 is disabled.
• Restore on AC Power Loss is set to Power Off.
• Deep Sleep tested.
• PCIe wake settings checked.

Additional observations

• Restart works 100% normally.
• Only shutdown is affected.
• After the failed shutdown, a short press of the power button starts the PC again.
• Holding the power button for 10+ seconds after the failed shutdown does not force it off.
• The only way to completely power it down is using the PSU switch.

Things that haven't changed

• I did not update the BIOS.
• I don't remember making any BIOS changes.
• I don't know if Windows installed a recent update automatically.

My questions

1. Has anyone seen an ASRock AM5 board fail to enter the ACPI S5 power-off state like this?
2. Could this still be a PSU issue even though restart and normal operation are perfect?
3. Is there any BIOS setting or AMD PBS/CBS option that could cause this?
4. Has anyone experienced this after a recent Windows update or BIOS firmware issue?
5. Is there anything else I should test before updating the BIOS or starting an RMA?

Any suggestions would be greatly appreciated. Thanks!

Basically modded the bioses for two of my 11th gen ES boards to have the new 2023 Secure boot keys

additionally modded my 13980HX D4(DDR4 ONLY) NON-ES board to have the new secure boot keys and the 132 microcode(best working microcode to prevent CPU degredation)

and thought I'd share for anyone with the same boards.

READ ALL OF THESE WARNINGS:

NOTE: Changing your secure boot settings can trigger bitlocker if you have it enabled, disable it first.

IMPORTANT NOTE: Before doing anything, make sure you have your password to your microsoft account, changing secureboot settings makes windows force you to put in your password and re-enable your pin/face/whatevers

NOTE: take a photo of your bios settings before you begin, you will be resetting them, you might want to set them back up and its easier if you have a reference, specially on an Eng sample board that may have loads of settings you had to set to get it stable.

Note: NO THE Eng sample bioses wont work on non-ES 11th gen boards.

THM570111 is compatible with the older 570106

Check your current bios versions to confirm

WARNING: the 11th GEN BIOSES WILL NOT WORK ON THE 6 CORE VERSIONS(ES OR NOT) OR THE NON-ES VERSIONS OF THE BOARDS

WARNING: The 13th Gen bios is for the HM770 based 13980HX DDR4 motherboard only.
It might not work on the ddr5 version, it might not work on lower end 13th gen HX boards, I don't know, if you do try it have a flash programmer like the CH341A and required adapters handy(cheap af and it works)

WARNING: MAKE BACKUPS, THE HOWTO TEXT FILE TELLS YOU HOW TO.

Also do this at your own risk, I'm not a helpdesk, I'm just here because some bios flashing veterans might find having the new secure boot keys on an erying bios useful.

Use the CSME discovery tool to work out what version of the CSME tools/ FPT64 you need to use to flash

also included instructions on how to update your ME firmware etc as I have done to my machines.

https://drive.google.com/drive/folders/1JNikQhar3nApPa3qSFQBOfBrKAJe-62n?usp=sharing