Hi all, wondering if I could get some technical support advice, I've just put together a pc and it's not posting no matter what I've tried by reading every other post I can find.

System: MB: B650m Pro RS BIOS: 1.28 PSU: Corsair RM750x CPU: Ryzen 5 7600 GPU: Sapphire Pulse rx7800 xt Drive: Crucial P5 2TB RAM: Corsair Vengeance 2×16GB 6000mhz cl36

So here are the troubleshooting steps I've tried so far -reseating all cables from PSU -trying to boot without GPU -reseating everything (RAM, CPU, cables again) -Clear CMOS -left trying to boot for 40 minutes as I've seen it can take some time -tried with one stick in each slot -Tried with the other stick in each slot -tried with a different set of ram

And I've tried the BIOS flashback with a 4gb usb drive formatted fat32 16kb partitions using both Windows and Rufus, using MBR partitioning, I've been renaming the file to creative.rom, and I've tried with 3 usb drives of varying ages and capacities, I'm using the correct slot, I've check that in the manual a dozen times, and I've tried with everything removed from the motherboard but the motherboard power, but every time after holding down the button for 3-5 seconds the light just stays solid green.

So at this point I'm pretty much out of ideas, and I'd welcome any other suggestions.

Update: this is one of 2 AM5 builds I was going to do this weekend, so I've built the other one, and it boots up fine, and I've swapped in the CPU and RAM from the system that won't post, and the CPU and RAM work fine, so it's definitely a motherboard issue, think I'm going to have to return it at this rate.

Update 2: Thanks everyone for your suggestions, I've ended up RMA'ing the board and they've decided it's faulty too, so just waiting on them to send the replacement out now.

Hey everyone, I’m pretty deep into troubleshooting this and could use some fresh eyes. I’ll lay everything out clearly.

System

• Motherboard: ASRock X870 Taichi Lite (AM5)

• CPU: 9800X3D

• RAM: Corsair Vengeance DDR5 2x32 GB

• GPU: Nvidia RTX 4080 Super (Gigabyte) gaming OC)

Original Issue

• The system was working and even booted into Windows at one point

• Then I had:

  • POST code 03

  • Then 40

  • Eventually froze at the ASRock splash screen

After that, the keyboard/mouse stopped working in Windows → instability

What I Did

• Removed the GPU to access the CMOS battery

• Pulled the CMOS battery and reset the BIOS

• Reinstalled GPU

Current State

• System now shows POST code 00

• No display

• Fans spin, but RGB on fans works/ AIO screen is blank, AIO pump (Lian Li)

BIOS Flashback Attempts

Trying to recover via Flashback:

Setup:

• USB formatted to FAT32 (full format, not quick)

• Only BIOS file on root (no folders)

• Using the correct BIOS:

  • X87ETCL4.10.ROM

  • Downloaded fresh from the ASRock site

• Tried with:

  • Original filename (no rename)

  • Proper extraction (not zipped)

• Used the correct Flashback USB port

• PSU ON, system OFF

Behavior:

• Flashback LED blinks ~3–5 times

• Then goes solid red immediately

• USB activity light flashes briefly, then stops

What I've Already Ruled Out

• Wrong BIOS file → verified correct board + version

• Incorrect extraction → confirmed good

• File naming issues → tested both approaches

• CMOS reset → done multiple times

• CPU reseated + cleaned + new thermal paste

• RAM reseated (1 stick, A2 slot)

• GPU reseated

• Power cables (24-pin + CPU EPS) reseated

Next Step

• Trying a different USB drive (smaller/older, possibly USB 2.0)

• I doubt this will change anything :(

Questions

1. Has anyone seen Flashback fail instantly like this, even with the correct file?

2. Could this indicate:

   • Dead BIOS chip?

   • Flashback controller failure?

   • Dead CPU?

3. Given it booted earlier, is it more likely the board got corrupted vs physically failed?

4. Anything else I should try before RMA?

Current Theory

• Either:

  • USB incompatibility (testing next)

  • OR motherboard/BIOS flash circuitry failure

Appreciate any help—this one has been a grind.

Just built a new PC and it won't boot.

Trying to update BIOS and I get the "solid green lights".

The only instruction I can find is "Please make sure that you plug the USB drive to the USB BIOS Flashback port".

But what should I do to not kill my MB?

Extract the USB drive? Turn the PSU power off? Press the bios button again?

I just got the motherboard and I only have the 24 pin cable from the power supply connected. It has been stuck in a flashing green light for the last 45 minutes.

What's going on? How do I safely abort this process safely!?

I'm now finding out that my USB drive might be too big since it's 16 GB instead of 8 GB or below.

So I just went to do a BIOS Flashback on my B550 Taichi from ASRock, using the usb in the rear I/O method, since I don't have a 3000 series CPU in order to do the BIOS update. However, when I press the BIOS Flashback button it blinks a red light (instead of what I was hoping, green). It blinks for a while and then stops. What does this mean?

Specs

Asrock b650i lightning wifi Ryzen 7 7700x Zotac 4070 Crucial pro 2TB 32 gb of ddr5 ram

I put the cmos jumper on the pins for about 3 seconds then took it off.

From what I've pieced together online is

Must be a USB 2.0 below 32GB (16GB preferably) I have this.

SanDisk 16GB Cruzer Blade USB 2.0 Flash Drive - SDCZ50-016G- B35, Black

Must be formatted to Fat32 or fat16

MBR Partition style

Raphael BIOSUBU.BIN for Ryzen 7 7700x

Last validated BIOS 1.28 I tried this version and 3.30

SSD is uninstalled

GPU is uninstalled

Hey everyone, I'm in the process of building a new budget PC and decided to go with the Ryzen 5 8500G paired with the ASRock A620M-HDV/M.2 motherboard. After installing everything (CPU, RAM, NVMe, PSU, etc.), I attempted to boot — but the system didn’t post. Instead, I got solid red lights on both CPU and DRAM indicators on the motherboard.

After doing some research, I realized this seems to be a common issue with this board-CPU combo — apparently the board often ships with an older BIOS that doesn’t support the 8500G out of the box.

I came across a Reddit post where someone had the exact same setup, and they managed to get it working by doing a BIOS flash using a USB drive. They formatted their USB to 2GB FAT16, renamed the BIOS file to CREATIVE.ROM, and used the BIOS Flashback button on the board to update it.

I’ve been trying to replicate the process, but things are getting confusing. The ASRock official instructions differ from what users are saying online.

ASRock doesn’t mention anything about renaming the file to CREATIVE.ROM

Some tutorials suggest different formats (FAT32, FAT, FAT16) and file names

There’s also no clear indicator on this board during BIOS flash, so it’s hard to tell if it’s working at all

At this point, I’m really frustrated. If anyone has successfully flashed the BIOS on this exact board (ASRock A620M-HDV/M.2) to get the Ryzen 8500G working, I’d really appreciate some help and a clear step-by-step.

Thanks in advance to anyone who can guide me. You’d be saving my sanity.