I've been collecting parts for this high-end build for about two years, and now it powers on but refuses to display anything. The fans and lighting work, but the motherboard shows red CPU and yellow DRAM debug LEDs. I initially powered it on for roughly 30 seconds, then shut it down to move it, not realizing the system might still have been training the memory.
The build uses a Ryzen 9 9950X3D with an MSI MAG B650 Tomahawk WiFi. The board's current BIOS may not support the CPU, so I expected to use BIOS Flashback first. However, the rear USB ports don't appear to detect flash drives or other peripherals, and Flashback never begins properly. I get a white light only while holding the button, rather than the blinking light associated with an active BIOS update.
I've tried leaving it for memory training, swapping and removing RAM, rebuilding the system outside and inside the case, checking seating and CPU socket pins, loosening the cooler, clearing CMOS, booting with only essential components, and preparing a correctly formatted and renamed USB drive. I also tried different component configurations, but still get no display or usable rear I/O. I'd really like to avoid replacing the motherboard unless it's truly defective. What should I check next, and what is the exact procedure for getting BIOS Flashback to work?
4 Answers
Installing another compatible AM5 processor would be a useful way to update the BIOS through the normal setup, but it isn’t necessary if Flashback works and it may not be practical financially. I would exhaust the powered-off Flashback procedure and several USB drives first. If none of them produce the expected blinking update light, the motherboard’s Flashback function or USB hardware may be faulty, making replacement or warranty service more likely than a CPU or memory failure.
Try another USB drive even if the current one is new and correctly prepared. Motherboard Flashback can be unusually picky about drive size, partition layout, and compatibility. A basic 8–16 GB drive formatted as FAT32 is worth trying, with only the BIOS file on it. Make sure the file is for the exact motherboard model and has been renamed using MSI’s required naming convention. If the indicator only stays lit while the button is physically held and never starts blinking after a press, the board probably isn’t accepting the drive or file.
For troubleshooting after the BIOS update, test the board with the minimum setup: motherboard, CPU, cooler, one RAM module in the recommended slot, power supply, and monitor. Try the monitor from both the graphics card and the motherboard video output, since the processor may provide integrated graphics. Leave the RTX card and storage disconnected until the system can reach the BIOS. Also inspect the rear I/O and Flashback port for damage or a misplaced connector.
I’ve already tried one RAM stick and a bare-minimum configuration, but I hadn’t tested the motherboard HDMI output. I’ll check that as well once I retry Flashback.
The CPU may simply be unsupported by the BIOS currently installed, so the CPU and DRAM LEDs aren’t necessarily evidence that either part is bad. BIOS Flashback should work without the CPU, RAM, storage, or graphics card installed. Leave only the motherboard’s 24-pin power and CPU power connected, turn the power supply on, but keep the computer itself powered off. Use the specifically labeled Flashback USB port, insert a FAT32-formatted drive containing the correctly renamed BIOS file, and press the Flashback button once rather than holding it. A successful update should blink for several minutes before stopping.
I had only tried pressing the button while the system was powered on, so doing it with the PC turned off is the first thing I’m going to retry. I was also holding the button to observe the light, but it sounds like a single press is the intended procedure.
The current drive is a new 16 GB model, and I did follow the formatting and filename instructions, but I’ll try a different small drive anyway. The lack of blinking is why I suspect the drive or Flashback port isn’t being recognized.