I've been collecting parts for this build for about two years, and now everything powers on but the system never reaches POST or shows an image. The fans and lighting work, but the motherboard's red CPU and yellow DRAM debug LEDs remain lit. The MSI MAG B650 Tomahawk WiFi needs a BIOS update before it can support my Ryzen 9 9950X3D, so I expected to use the board's Flash BIOS button first.
The trouble is that BIOS Flashback doesn't seem to start. I formatted a 16GB USB drive, renamed the BIOS file as instructed, and tried the designated rear USB port. The button only produces a solid white light while I hold it; I never get the blinking indicator that should mean the update is running. The rear USB ports also don't appear to detect peripherals. I accidentally powered the system off after about 30 seconds during my first attempt, before realizing the board might be doing memory training.
I've tried leaving it training overnight, swapping the RAM sticks and using one stick at a time, rebuilding the system outside the case, checking the CPU socket and connections, loosening the cooler, clearing CMOS, removing unnecessary components, and attempting Flashback with only the basic parts connected. I'm worried the motherboard may be faulty, but replacing components would be difficult financially. What should I check next, and is there anything specific about the Flashback process I might be getting wrong?
4 Answers
The CPU support issue is the main blocker right now. Until the BIOS is updated, the board may never POST, so the CPU and DRAM LEDs aren’t necessarily evidence that those parts are bad. BIOS Flashback should work without the CPU, RAM, storage, or graphics card installed, but the motherboard’s 24-pin power and CPU/EPS power connectors need to be connected.
Make sure the PC is fully switched off, use the exact Flash BIOS USB port, and press the button once rather than holding it. A successful update should normally produce a blinking LED for several minutes. If it only lights while being held, the board probably isn’t accepting the drive.
Trying another compatible AM5 processor would confirm the motherboard and let you update the BIOS, but that’s only practical if you can borrow one. Since you’re trying to avoid buying another CPU, getting Flashback working with a different USB drive and the system powered off is the best next step. The rear USB ports not detecting normal peripherals before POST doesn’t necessarily mean they’re defective.
For the black-screen testing, connect the monitor to the motherboard’s HDMI output as well as the graphics card output. That won’t solve an unsupported BIOS, but it can rule out a GPU or display-output issue once the board starts POSTing. Also double-check the EPS CPU power cable, not just the large motherboard connector.
Try a different USB drive even if the current one meets the size requirement. Some boards are surprisingly picky about Flashback media. Use a small drive, format it as FAT32, put only the correctly renamed BIOS file on it, and connect it to the specifically labeled Flash BIOS port. For the cleanest attempt, remove the CPU, RAM, GPU, SSD, and other USB devices, leaving only motherboard power and the PSU connected.
The current drive is a new 16GB SanDisk, but I’ll still try another one if the powered-off attempt fails. I’ll also strip the board down to just its power connections and the USB drive.
I had only tried Flashback while the system was powered on, so I’m going to repeat it with the PC shut down. I was pressing and holding the button to see what the LED did, but I’ll try a single press as well.