I have a couple videos on the MSI boards, but none of the AM5 ones yet. So maybe things are different however... It's kind of odd that the CPU power 1 is on the left on that board... but I mean it's -getting power- to the flash bios circuit so you shouldn't need both powered on (might not hurt just to make sure that something else maybe isn't getting power... not sure). The B550-A Pro only has 1 CPU Power Connector so... it's slightly different. I did videos on a B550-A Pro board, and when you push the flash button it does a few quick blinks, and then starts blinking steadily. At some point (and it can take a while), it will stop blinking and the CPU light will stay on. Seeing as this post is from 2 hours ago, if it's still blinking I would assume that it is not able to update. You should be safe to power off the power supply. Make sure that the Bios file is renamed to MSI.ROM exactly and is in the root folder of the USB drive that is Fat32 Formatted. I have a 2 or 4gb drive that I do my updates with because some larger ones seem to have issues sometimes (but not always). Answer from kardall on reddit.com
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Reddit
reddit.com › r/asus › help! b550 tuf bios flashback led won't stop blinking
r/ASUS on Reddit: HELP! B550 TUF BIOS Flashback LED won't stop blinking
December 6, 2020 -

I flashed the bios with just the power supply and nothing else first and it seemed to go fine - blinked for a while and then stopped. I then put the rest of my build together and after turning on the power supply the BIOS flashback led won't stop blinking. I plugged the USB back in and pressed the button again and it blinked quickly and cycles between blinking quickly and slowly. The system will not post.

Parts:

Mobo: ASUS b550 TUF gaming

CPU: Ryzen 9 5900x

GPU: 3080 Strix

PSU: Corsair RM 850x

Memory: crucial ballistix 3200 mhz 32 gb

CPU cooler: Be quiet dark rock 4

SSD: SK Hynix m.2

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Asus
rog-forum.asus.com › t5 › gaming-motherboards › bios-flashback-blinking-can-t-power-on › td-p › 1067009
BIOS flashback blinking / can't power on - Republic of Gamers Forum - 1067009
January 7, 2025 - Recently I tried again , and again it only succeeded within 1-2 seconds after turning on the power supply, until the flashback led flashes. I have no idea why it does it.A few minutes later I tried again and it started without any errors. Randomly good or bad. ... Any news ASUS? I REALLY don't want to send the board for repair for this. ... Theres another post with same issue and solution for him was to remove the actual BIOS button in the back ... ASUS PG32UCDMR Brick - Black Screen, Orange Blinking LED, Detected by Windows in Gaming Monitors Wednesday
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Tom's Hardware Forum
forums.tomshardware.com › home › motherboards
Question - Flashing Bios - Continuously blinking (MSI B550 Gaming Plus) | Tom's Hardware Forum
January 17, 2025 - on some boards the blinking speed will slow as its nearly finishing.. (not on all boards).. . if its not done after the 40+ minutes. power of.. take out usb stick,, add cpu and ram, and power ok.. it should start to boot cycle. (training ram and going through the bios boot sequence.
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MSI
forum-en.msi.com › home
Updating Bios via Bios Flash Button - LED doesn't stop ...
November 29, 2020 - TPM disappears on first boot after long shutdown - BitLocker recovery + Code 45 + “No TPM device found” in BIOS (Modern 14 H / D13MG)
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Reddit
reddit.com › r/msi_gaming › hey all, when i attempt to do a bios flashback, it blinks three times and stays solid. see comments
r/MSI_Gaming on Reddit: Hey all, when I attempt to do a bios flashback, it blinks three times and stays solid. See comments
December 21, 2022 - Chose FAT32 with no label and no drive letter, and make sure to uncheck the "Quick Format" box because we want a pristine, virgin, stripped and waxed flash drive. It should take a few moments. After all of that, copy over your "MSI.ROM" file and give Flashback another go ...
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Visioncomputers
visioncomputers.com › asus-bios-flashback-looping
ASUS BIOS Flashback Looping Fix | Vision Computers | Vision Computers
March 22, 2026 - Your ASUS motherboard's BIOS Flashback LED has been blinking for 20 minutes, 40 minutes, maybe over an hour. The process should take 3 to 8 minutes. If that LED is still cycling, something went wrong and the flash is not progressing. This guide walks you through every cause of a BIOS Flashback loop, from a physically shorted button to a corrupt BIOS file, and shows you how to break the cycle safely.
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Reddit
reddit.com › r/asus › help! bios flashback led is blinking and pc won't start
r/ASUS on Reddit: HELP! BIOS flashback LED is blinking and PC won't start
November 13, 2024 -

Last night I turned off my PC as usual, nothing strange happened, this morning I went to turn on the PC and it didn't start, not even the RGB, not anything. Then I noticed a green light blinking on the back, it was the bios flbk, I didn't know what it was until now that I researched it. Tried everything to fix it, removed de CMOS, used a screwdriver to turn it on, checked the button itself, I tried to update the bios with a flashdrive, unplugged all the cables from the back, move it to my table and I connected the USB on the bios port, and I let it run for several minutes, but after 30 minutes I thought my MB was dead, so I just let it there to do some other things, came back 2 hours later, pressed the power button, and it booted, I got excited, turn off the pc again, put it back at my desk, plugged everything back, and now it doesn't start again, I don't know whats wrong, its been another 30 minutes, and it's still blinking, am I doing something wrong? And how did this happen if I never have messed with the bios or this button?

Its an Asus prime x670-P WIFI

Find elsewhere
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Asus
zentalk.asus.com › t5 › motherboards › prime-b650m-a-wifi-bios-flashback-light-keeps-blinking-and-pc › td-p › 441606
PRIME B650M-A WIFI BIOS Flashback light keeps blinking and PC won't boot
October 4, 2024 - Today I have also tried to just use the BIOS flashback to install the BIOS ver 3024 again but the LED was still blinking after an hour so I gave up and cut the power for ~30s again, after which the PC did boot normally but after shutdown the issue is happening again.
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H|ard|Forum
hardforum.com › [h]ard|ware › motherboards › amd mobos
FLBK_LED started blinking after shutdown | [H]ard|Forum
March 29, 2021 - Normally, if you hold the button on the back down for a few seconds you would see that light flash a few times and then it would attempt to do the BIOS flash if there was a drive with a Bios image on it attached to the right port. As for why yours is stuck on or how to turn it off, sorry I'm not sure, possibly the button got inadvertently pushed. Maybe try removing all power for a while, or do a CMOS clear, or flash the BIOS (there's been a rash of new X570 Bios's lately anyway).
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Asus
rog-forum.asus.com › t5 › overclocking-tweaking › bios-led-won-t-stop-flashing › td-p › 240002
Bios LED won't stop flashing - Republic of Gamers Forum - 240002
March 7, 2024 - how long has it been blinking.. Be a little careful when doing this, a interrupted bios update, can result in a faulty bios.. and major errors. it blink for a while (around 1 min maybe), slow, a little faster, fast.
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ASUS
asus.com › support › faq › 1038568
[Motherboard] How to use USB BIOS FlashBack™? | Official Support | ASUS Global
April 9, 2026 - 7. Press the BIOS FlashBack™ button for three seconds until the FlashBack LED blinks three times, indicating that the BIOS FlashBack™ function is enabled.
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Asus
rog-forum.asus.com › t5 › gaming-motherboards › asus-z790-h-bios-flashback-led-blinking-and-pc-not-starting-no › td-p › 1063107
Solved: ASUS Z790-H Bios flashback LED blinking, and pc no... - Republic of Gamers Forum - 1063107
January 7, 2025 - 3) Press and hold the Bios Flashback button until the led starts blinking, then release. The blinking should get faster as it goes then stop when completed, should take a few minutes.
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GameRevolution
gamerevolution.com › home › guides › how to fix asus or rog bios flashback not working fix: what to do if the light stays solid
How to Fix Asus or ROG BIOS Flashback Not Working Fix: What to Do if The Light Stays Solid - GameRevolution
March 31, 2023 - Unfortunately, the official ... you use and how it’s formatted. ... With the PC powered off, hold the BIOS button on the rear I/O panel for three seconds. The BIOS button should blink three times, then start blinking ...
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Tom's Hardware Forum
forums.tomshardware.com › home › motherboards
Question - BIOS flash stuck eternally on fast blinking, help needed, system won't boot | Tom's Hardware Forum
August 14, 2021 - Then I unplugged everything from the motherboard but the CPU and ATX power connectors, and it seemed to work. The flash bios led starts blinking, then the blinking gets faster and the cpu debug light comes on, and then it keeps blinking at the same rate for the rest of time, or at least for the 9 hours I gave it before trying a different usb.
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Reddit
reddit.com › r/asus › bios flashback blinking for hours
r/ASUS on Reddit: BIOS flashback blinking for HOURS
September 29, 2022 -

It’s been 2 hours since I started the BIOS flashback. It’s just been blinking this whole time. No feedback on the monitors; no indication of failure or success. I think I may have formatted my thumb drive incorrectly, but shouldn’t that give me a failure? How long should I let this continue for? How can I safely stop it?! Here’s a little video.

The board is a ROG crosshair viii dark hero.

SOLVED: I got on tech support with ASUS and they told me to press the cmos reset button, so I did that, redid the flash correctly, then after some bios settings, I'm back in Windows. Phew! If you're thinking of doing a bios flash and you're in windows, USE THE EZ FLASH THING! This sucked! <3

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Reddit
reddit.com › r/asus › bios flashback led flashing and pc won’t boot, any help?
r/ASUS on Reddit: BIOS flashback LED flashing and PC won’t boot, any help?
January 10, 2022 - After doing everything I could think of, reseeding the RAM, Clearing the CMOS and checking the cables I noticed that the BIOS LED was flashing. So I tried looking for similar cases and I happen upon a thread on the ROG Forum which booted my PC up. Take note this is not a solution as it still happens if you don't time it right. the problem with no boot still persists, if I am not following the exact steps I mentioned before: ... Push the Power Button before the first blinking of the Flashback LED on the rear start to happen.
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Reddit
reddit.com › r/computerhelp › pc won't boot unless quickly unplugging and replugging power and bios led blinking
r/computerhelp on Reddit: PC won't boot unless quickly unplugging and replugging power and Bios LED blinking
October 21, 2025 -

So in this video the PC bios LED is blinking while the pc is turned off and power is plugged in.

Things I have tried :

  • Flashing bios with 2 different 16gb flash drives formatted to fat32 MBR

  • Unplugging RAM

  • Unplugging PSU and testing it (Since I wasn't aware of the bios issue before)

  • resetting CMOS battery and using the jumper to reset bios (followed the manual to a T)

What worked was something stupid as you see in the title which I read in a reddit comment, "as soon as the power is plugged click on the boot button before LEDs are on" which Indeed worked and I even could reboot my PC a few times, but shutting it down, it happens again.

Now this is not a new PC and the problem happened suddenly I did not change a thing, just was using it normally and went to sleep, the next day this happens. So I did not attempt any bios update or whatnot.

SPECS :
ROG STRIX B650E-F GAMING WIFI
Seasonic Vertex-PX 1200 80+ Platinum
G.Skill Trident Z5 RGB 32 GB (2 x 16 GB) DDR5-6000 CL30
Ryzen 7 7800X3D
RTX 5090
Windows 11 24H2 (26100.6899 build)
Bios 3279 (Latest)

Please let me know if I could provide further info and I will edit the OP with it.

UPDATE : the solution provided by u/jOta39 works as a nice workaround

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ASRock
asrock.com › support › QA › FlashbackSOP.pdf pdf
Page 1 / 4 ASRock Flashback Feature User guide
Press the BIOS Flashback Switch for about three seconds. Then the LED starts to blink.