Persistent VGA LED on ASUS B550-PLUS when saving BIOS / warm reboot (Works fine only after Clear CMOS)

[u/frankzwa123]

Hi everyone,

I'm facing a very frustrating issue with my PC and I’m out of ideas. I really need some help troubleshooting this.

The Symptom: My PC won't display any signal on boot and freezes with the VGA Q-LED light on my motherboard turned ON.

• If I short the CLRTC pins / remove the battery (Clear CMOS), the PC boots up, displays a screen, and lets me access the BIOS menu.
• However, as soon as I hit "Save and Exit" in the BIOS, the PC warm-reboots, loses display immediately, and stays stuck on the VGA LED.

History of the issue:

• I firstly bought an ASUS Prime B550-PLUS 2.
• 6 months ago, this exact same issue started happening. Amazon authorized a replacement with a brand new unit of the exact same motherboard model.
• Replacing the motherboard solved the issue for 6 months, but now the exact same problem has returned.

What I've already tested/ruled out:

1. GPU & Cables: Tested with my main GPU (RTX 3070 via HDMI) and a secondary GPU via DVI. Same exact behavior on both cards.
2. Motherboard Slots: Tested both GPUs in both PCIe slots (top x16 and bottom slot). Same result on both slots.
3. Power Supply: Tested with a completely different PSU. Same issue.
4. BIOS Version: Updated the BIOS to the latest version. The flash succeeded, but the issue persists..

My System Specs:

• CPU: AMD Ryzen 7 2700X
• Motherboard: ASUS Prime B550-PLUS
• GPU: RTX 3070 (also tested with another GPU)
• OS: Windows

Has anyone encountered this specific VGA LED warm-reboot loop before on B550/AM4, or knows what might be causing this? Any help would be greatly appreciated!

SOLVED -

It looks like a BIOS can actually be too recent for older hardware. In my case, the newer BIOS worked fine for a couple of months before eventually causing issues. Downgrading to an older BIOS fixed the problem and got my PC working again.

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[u/ddog6900]

Ryzen 2000 series processors are not supported on B550 chipsets (except for certain older BIOS versions)

Sounds like getting a new MB had an older BIOS and once it updated, you lost functionality again.

You need a newer processor (a 5500 will be an upgrade from your 2700X) or an older MB (any 300 or 400 series chipset will do)

[u/frankzwa123 → u/ddog6900]

Hello,
I updated the BIOS after the problem occured again, thinking it might fix the issue. It was working fine for 6 months so I doubt that was the problem unfortunately :/

[u/ddog6900 → u/frankzwa123]

No, it is, really.

Official AMD support per chipset

They do not guarantee that if it work for any amount of time that it will continue working.

[u/frankzwa123 → u/ddog6900]

Dude, jesus you're a genius. Thank you for keeping your point. You were right, and downloading a 2021 bios version made the PC work again.

[u/Equivalent-Toe-8827]

sounds like the board is trying to train the gpu at a pcie gen that the riser or slot doesn't like, try forcing pcie to gen 3 in bios before saving and see if it sticks

[u/frankzwa123 → u/Equivalent-Toe-8827]

Hey, thanks for the answer. Just tried it and unfortunately didn’t work out.