!!! Warning: Z490 boards - problem with recent BIOS updates !!!

citay

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There is a common problem with the latest BIOS updates for Z490 boards: The update seems to finish, the PC reboots, but then it's stuck with the EZ Debug LED "CPU" being on.

The danger has first appeared with the April/May 2021 BIOS update (changelog: "Improved Audio compatibility"), and may continue with newer updates as well, potentially causing the same issue: The board can become unusable / "bricked" because of a failed flash process.

Note that there is no risk of this with BIOS updates for MSI mainboards using other chipsets (like Z390, B460, Z590, B560, Z690, B660, X470, B450, X570, B550, and so on).
This can only happen on MSI Z490 boards. People with other boards can update normally.

The first reports about a Z490 BIOS update causing problems was at the beginning of May 2021: z490 Tomahawk CPU Debug LED Stuck on after latest BIOS update
Then in May 2021, this thread: Warning : V17 bios for Z490 Gaming Edge Wifi release Monday may brick your board., and several more after.

I have found no reports of problems with any of the earlier BIOS updates, only with the ones from mid-2021 and newer. Also, this problem doesn't happen all the time, otherwise this forum would be absolutely flooded with complaints. But it is a real danger, as you will see below when i list some of the affected users.

Normally i'm all for updating the BIOS, and i do it pretty much immediately on my boards whenever a new BIOS is released. And this Z490 issue is the first such problem i ever saw. But the main problem is: Unlike some newer-generation boards, most of the Z490 boards have no way of recovering from it. For most people, the only way to solve this would be to RMA the board, or try their luck with an external BIOS programming device. The only Z490 boards where it's no problem are the two sister boards MEG Z490 UNIFY and ACE, and the MEG Z490 GODLIKE, because those three have a USB Flashback function (Flash BIOS Button). There you can flash back to an older version and the board works again, or you can even flash the newest version until it works (once the BIOS is successfully flashed, even the three newest versions will work fine).

The newer Z590, Z690 and Z790 boards now almost all have a Flash BIOS Button (and corresponding USB port) on the rear I/O panel through which users can "force-flash" the BIOS in case of problems. So i guess MSI rather add that function everywhere now, instead of dealing with RMAs of bricked boards when something goes wrong. Once you have this "USB Flashback" feature on a board, a problem like this becomes harmless, because you can just re-flash the latest BIOS and make it work again.

I have researched about all the users i could find that have been affected by this, so everyone can see the full scope of the problem. I don't think i exaggerate when i claim that this is a huge problem for MSI and their reputation, and to my knowledge, they have not reacted until this day. They released the September BIOS update for Windows 11 compatibility, and while such an update went well on my Z590 board at the time, as expected (plus it has the safety net of the Flash USB Button), there are still reports of the similar Z490 update potentially causing this problem there. Each day, there are many people updating their BIOS on MSI mainboards without any issues, and only on Z490 boards we see this kind of problem.

As a longtime MSI user, this kind of problem with the Z490 boards is unacceptable, even if i don't have a Z490 board myself.
Therefore, i decided to try to bring further attention to it, so hopefully MSI can do something about it as soon as possible.

Update October 7, 2021: MSI are now seemingly aware of this issue, as was confirmed on a German forum by an official MSI account. I will update this post/thread if there is any progress.

Update October 29, 2021: A user received a link from MSI with a tool for manual flashing from the command line. However, this is just an interim solution if you absolutely want to update to the newest Z490 BIOS and reduce the risk of failure. We are still waiting for them to upload new BIOS updates where this potential problem is 100% fixed.

Update March 6, 2022: Still no solution from MSI.

Update August 17, 2023: Still nothing from MSI, although there are considerably less cases now than there have been two years ago, we barely get any new victims. So maybe the newest BIOS versions are way less problematic again. As for updating an MSI Z490 board, i now recommend using the Forum Flash Tool as linked here. There has been no corrupt Z490 BIOS reported with it yet.


If the problem already happened, the best do-it-yourself solution by far is this kind of method with an external flash programmer (bit more info here), it has a 100% success rate from what i have read so far. Meaning, more or less everyone that seriously tried that method could eventually flash their BIOS with it and get the board back to a working state. So for everyone wanting to avoid a possibly lengthy RMA process, this is a viable option. The programming device is quite cheap, but it involves a bit of research and spirit of adventure. Luckily, there are good guides about it on Youtube for example.


One final word: It is important not to be put off from doing BIOS updates altogether by this. BIOS updates fix bugs, add new features, and they even improve performance. It is extremely rare that a whole line of mainboard models has such a potential problem. So, nobody should conclude never to do any BIOS updates again, that would be the wrong thing to learn from this. Instead, once this problem is fixed for the Z490 boards, the BIOS updates can once again be an important way to make the system work better, faster, and with less bugs. On other boards with a Flash BIOS Button as a safety net, there is literally no reason to shy away from any BIOS updates. Even here with the Z490 boards, whenever users with the the boards Z490 ACE, UNIFY or GODLIKE were affected, they could easily recover from it using the Flash BIOS Button. This problem could only become so big because all the other Z490 board models from MSI didn't have the Flash BIOS Button yet.


Statistics:
Affected total users (from this list and from further replies to this thread): 183
Users that could fix it themselves using the Flash BIOS Button (
Z490 ACE/UNIFY/GODLIKE): 9
Users that could fix it themselves using an external programming device: 12
Users who did an RMA with the vendor or MSI for a fix/replacement: 56
RMA declined because of existing unrelated damage on the board: 4
Users that bought a new board themselves: 9
No further information / no RMA yet: 93

Users that updated via MSI Center / Dragon Center Live Update: 85
Users that updated via M-FLASH in the BIOS: 66
Update method unknown:
32


List of affected users i have found on the forum, as of first posting this thread:

(Roughly in chronological order)

User: @datz.bunz
Date of failed flashing: May 2021
Affected board model: Z490 Tomahawk
CPU: ?
Flashing method used: M-FLASH
Attempted update to BIOS version: 7C80v18
Result: Stuck at EZ Debug LED "CPU" after update. Bought a replacement board (ASUS)

User: @mace014ea02cd
Date of failed flashing: May 2021
Affected board model: Z490 Tomahawk
CPU: 10700K
Flashing method used: M-FLASH
Attempted update to BIOS version: 7C80v18
Result: Stuck at EZ Debug LED "CPU" after update. Got a replacement board

User: @dr_overflo153302df
Date of failed flashing: May 2021
Affected board model: Z490 Tomahawk
CPU: 10700K
Flashing method used: M-FLASH
Attempted update to BIOS version: 7C80v18
Result: Stuck at EZ Debug LED "CPU" after update. Bought a replacement board

User: @sixpackvbal129b02ae
Date of failed flashing: May 2021
Affected board model: Z490 Tomahawk
CPU: ?
Flashing method used: M-FLASH
Attempted update to BIOS version: 7C80v18
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI, got his repaired board back

User: @mark.hadda156c02dd
Date of failed flashing: May 2021
Affected board model: Z490 Tomahawk?
CPU: 10850k
Flashing method used: M-FLASH
Attempted update to BIOS version: 7C80v18
Result: Stuck at EZ Debug LED "CPU" after update.

User: @mickh5494
Date of failed flashing: May 2021
Affected board model: Z490 Gaming Edge
CPU: ?
Flashing method used: M-FLASH
Attempted update to BIOS version: v17
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI?

User: @kenneth.cotma151802d1
Date of failed flashing: May 2021
Affected board model: Z490I Unify
CPU: 10700K
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. RMA through vendor, sent to MSI for repair

User: @anglnotre15dd02f0
Date of failed flashing: May 2021
Affected board model: Z490 Gaming Plus
CPU: 10600K
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. RMA, got his repaired board back with older BIOS vA6 on

User: @lesurvenan152302d4
Date of failed flashing: May 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: 10600K
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v17
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI?

User: @sa3aa14e902d9
Date of failed flashing: May 2021
Affected board model: Z490 Gaming Edge
CPU: 10700K
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v17
Result: Stuck at EZ Debug LED "CPU" after update. Goes "back to ASUS"

User: @jallu_col129b02ae
Date of failed flashing: June 2021
Affected board model: Z490 Gaming Carbon Wifi
CPU: 10900K
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v18
Result: Stuck at EZ Debug LED "CPU" after update. RMA denied due to small scratch on the board. Bought a replacement board from different brand

User: @Own3d
Date of failed flashing: June 2021
Affected board model: Z490 Gaming Edge Wifi ?
CPU: ?
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI

User: @luis.stuardo2151c02d3
Date of failed flashing: June 2021
Affected board model: Z490 Gaming Carbon Wifi
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. It will be "his last board from MSI"

User: @tehjacku151402ce
Date of failed flashing: June 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. RMA denied by MSI (didn't go into detail), got a replacement through insurance

User: @mark.robinson198127b02ab
Date of failed flashing: June 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update.

User: @dj3for10
Date of failed flashing: June 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. "Contemplates life in front of dead PC"

User: @jwilby8160102f6
Date of failed flashing: July 2021
Affected board model: Z490 Gaming Carbon Wifi
CPU: 10700K
Flashing method used: M-FLASH
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA through vendor

User: @ferran.duarr157e02dd
Date of failed flashing: July 2021
Affected board model: Z490I Unify
CPU: 11700
Flashing method used: M-FLASH
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA through vendor

User: @Rubik
Date of failed flashing: July 2021
Affected board model: Z490I Unify ?
CPU: ?
Flashing method used: M-FLASH
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. Successfully repaired it by using a BIOS programmer,

User: @janschulteortbec154a02d3
Date of failed flashing: July 2021
Affected board model: Z490I Unify ?
CPU: ?
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v19?
Result: Stuck at EZ Debug LED "CPU" after update.

User: @hardcore_gamer29
Date of failed flashing: July 2021
Affected board model: Z490 Tomahawk
CPU: 10900K
Flashing method used: M-FLASH
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA through service center, got his repaired board back

User: @yamei031154f02d7
Date of failed flashing: July 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: 10900K
Flashing method used: ?
Attempted update to BIOS version: v18
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI

User: @saokirito93156102df
Date of failed flashing: July 2021
Affected board model: Z490 GAMING EDGE WIFI
CPU: 10600KF
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update.

User: @jwilby8160102f6
Date of failed flashing: July 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: 10700K
Flashing method used: M-FLASH
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA through vendor

User: @gmbeas160158102e0
Date of failed flashing: July 2021
Affected board model: Z490 Tomahawk
CPU: 10700K
Flashing method used: ?
Attempted update to BIOS version: v18
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI?

User: @mohdrodz15bf02ed
Date of failed flashing: July 2021
Affected board model: Z490 ?
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA

User: @mikemauge154a02d7
Date of failed flashing: July 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: 10900
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v17
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI, got his repaired board back with BIOS v17 on

User: @xsketchyfruit12fc02b9
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Pro Plus
CPU: 10400
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v19?
Result: Stuck at EZ Debug LED "CPU" after update.

User: @yxh93021154502dc
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Pro Plus
CPU: ?
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update.

User: @John Eisberg
Date of failed flashing: August 2021
Affected board model: Z490 UNIFY
CPU: 10900K
Flashing method used: ?
Attempted update to BIOS version: vA9
Result: Stuck at EZ Debug LED "CPU" after update. Used "Flash BIOS Button" method to force-flash to BIOS vA8, board works again

User: @aaronpeigh
Date of failed flashing: August 2021
Affected board model: Z490 UNIFY
CPU: 10850K
Flashing method used: ?
Attempted update to BIOS version: vA9
Result: Stuck at EZ Debug LED "CPU" after update. Used "Flash BIOS Button" method to force-flash to BIOS vA8, board works again

User: @dan.pahal125b02a7
Date of failed flashing: August 2021
Affected board model: Z490 Tomahawk
CPU: 10700K
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v18?
Result: Stuck at EZ Debug LED "CPU" after update. RMA

User: @amichele154f02db
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Plus
CPU: ?
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: vA8
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI?

User: @j0sefuz115d402ee
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: ?
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: v18
Result: Stuck at EZ Debug LED "CPU" after update.

User: @mikkl1620
Date of failed flashing: August 2021
Affected board model: Z490 Tomahawk
CPU: 10600K
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. RMA denied due to slightly bent pins in the CPU socket. Bought a replacement board "Z590 Tomahawk"

User: @yohan.vandevell154002e1
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Edge Wifi
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. Opened a ticket with MSI

User: @jonathan84012e802b5
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Carbon Wifi
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update.

User: @takocankol
Date of failed flashing: August 2021
Affected board model: Z490 ?
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update.

User: @christoph.urba128d02aa
Date of failed flashing: August 2021
Affected board model: Z490 Gaming Plus
CPU: ?
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: ?
Result: Stuck at EZ Debug LED "CPU" after update. Wants to attempt manual BIOS flash with CH341A EEPROM programmer,

User: @seeknay7415ae02f0
Date of failed flashing: September 2021
Affected board model: Z490 Gaming Carbon WIFI
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI. "Very unlikely he will buy another MSI board after this"

User: @mastersap157d02db
Date of failed flashing: September 2021
Affected board model: Z490 Gaming Carbon WIFI
CPU: ?
Flashing method used: ?
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update. RMA through MSI?, got a new board of the same model

User: @stro152c02d9
Date of failed flashing: September 2021
Affected board model: Z490 Gaming Edge
CPU: 10500
Flashing method used: M-FLASH
Attempted update to BIOS version: v19
Result: Stuck at EZ Debug LED "CPU" after update.



Everyone with the same problem on Z490 that doesn't find themselves on the list, feel free to reply here using the same format, here is a template:
Date of failed flashing:
Affected board model:
CPU:
Flashing method used:
Attempted update to BIOS version:
Result: Stuck at EZ Debug LED "CPU" after update.

Whenever i have seen your reply and included it in the statistics, i will give a "thumbs up" for it to thank you for your participation.

Also, feel free to refer to this thread in your communication with the vendor or with MSI. Hopefully MSI will finally start to recognize this problem and do something about it.

Someone asked me if they can thank me for my work by sending me something via Paypal: Yes, that's possible, just write me a message and i'll tell you my Paypal 😉
 
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7C79v16 is the last 100% safe version for the Z490 Gaming Edge Wifi. The three newer ones are potentially dangerous, i'm afraid.
 
Hi
Are there any known issues updating the BIOS on older chipsets? I have z370 gaming pro carbon and I'm going to buy rtx 30xx. According to data from the Msi website, I should update the bios. Is there a risk of the motherboard freezing?
 
No, this particular problem can only happen on Z490 (and there only with the three most recent BIOS updates).

Boards based on other chipsets are not affected.
 
Date of failed flashing: April 4, 2022
Affected board model: MPG Z490 GAMING CARBON WIFI
CPU: Intel i9 10900
Flashing method used: MSI/Dragon Center Live Update
Attempted update to BIOS version: Latest for Windows 11
Result: Stuck at EZ Debug LED "CPU" after update.
RAM: HyperX Predator DDR4 RGB 16GB kit 4000MHz CL17 DIMM XMP

I made the purchase through Amazon Mexico and I already spoke with MSI. From the USA portal I was able to raise the RMA to be attended from Mexico and they already received it.
I only have the question if with the RMA it is ensured that they fix it or change it at no cost?
 
I made the purchase through Amazon Mexico and I already spoke with MSI. From the USA portal I was able to raise the RMA to be attended from Mexico and they already received it.
I only have the question if with the RMA it is ensured that they fix it or change it at no cost?

I'm not too familiar with RMAs in general but in my case (Z490 Gaming Edge Wifi) it was clearly a brand new replacement.
I had made sure to remove everything removable from the board prior to shipping. I only paid for the shipping to send it to MSI Canada.
The board I received had all stickers and removable parts. It didn't come in a brand new box but it was manufacturer wrapped.
 
Date of failed flashing: April 8th, 2022
Affected board model: MSI z490 Carbon gaming wifi. (No cool bios button to fix it) :(
CPU: i7-10700K
Flashing method used: flash in bios menu
Attempted update to BIOS version: Newest
Result: Updated to 100% and rebooted, then stuck at EZ Debug LED "CPU".

RMA. This pos tomorrow, hopefully they can refresh the bios and I won't have to redo windows.

I would hate losing everything on my c: drive. I don't have another pc capable of reading NVme drives to backup. :( In 20 years of pc building this is the first time ever the official bios bricked my motherboard. Its really completely unacceptable.

Edit** I see they make a reader now for NVme to USB.
What does everyone think? Just ditch this motherboard and upgrade? If you can't upgrade the bios going forward, without risk of bricking it, is it worth keeping?
 
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Just ditch this motherboard and upgrade? If you can't upgrade the bios going forward, without risk of bricking it, is it worth keeping?

Well, if you get it back with the newest BIOS installed, then you won't have to update the BIOS ever again, there most likely won't be any new versions for Z490. Maybe they bring out one new version, if they tackle this potential bricking problem one day. Other than that, i don't think there will be another update. For all the older boards, the updates usually stop with the "Windows 11 supported" one.
 
And today it was my turn. MEG Z490 Unify with 10700K CPU will not start after BIOS upgrade from the Windows app. The BIOS upgrade button does not work either. When using it, it first flashes slowly 3-4 times, and a couple of seconds pause while the fans spin up and the board powers on, and then the BIOS-button rapidly flashes forever. (Or at least 5 hours until I gave up.) The 2 digit digital display next to the reset button on the board shows "--" and the CPU diode is active. This will be a sad weekend. :(
 
And today it was my turn. MEG Z490 Unify

About the Flash BIOS Button / USB Flashback, the main problem is that it is extremely picky about the USB drive/stick you try to use for it.
Basically, you have to keep trying with different USB sticks until they find one that works (the cheaper the USB stick, the better, from the feedback i got). It should take around 5 minutes of a certain kind of blinking for the process to complete. If it keeps blinking for longer, then it failed. If it doesn't start the certain kind of blinking, then it also failed. Also read here.

So don't give up easily, i'm sure you can eventually recover from the BIOS bricking problem with the Flash BIOS Button on your board.
 
About the Flash BIOS Button / USB Flashback, the main problem is that it is extremely picky about the USB drive/stick you try to use for it.
Basically, you have to keep trying with different USB sticks until they find one that works (the cheaper the USB stick, the better, from the feedback i got). It should take around 5 minutes of a certain kind of blinking for the process to complete. If it keeps blinking for longer, then it failed. If it doesn't start the certain kind of blinking, then it also failed. Also read here.

So don't give up easily, i'm sure you can eventually recover from the BIOS bricking problem with the Flash BIOS Button on your board.

Thanks for the encouragement. Much appreciated and needed. 😊

I have tried all kind of USB-sticks I have found at home, but so far no luck. Some of them just flashes as described in my first message. Some of them flashes slowly for maybe 5-10 seconds and then stays constantly on, and some others flashes slowly and then goes dark. Some of these are fairly new USB 3.0 sticks, so I did not expect them to work, but some are quite old. I will continue searching.

Or anyone know where confirmed working USB-sticks are available for sale? Used or new does not matter as long as it fixes the BIOS. MSI should actually provide these IMHO.

The USB-sticks below does not work with my MEG Z490 Unify.
20220409_132521-mini.jpg
 
For reference, if anyone is trying to prepare a USB-stick to use with the BIOS flash button, these are the diskpart commands I use:

list disk
select disk #
(Replace # with the number of the USB-stick disk.)
clean
convert mbr
create partition primary size=500
(size=500 might not be needed, but just in case...)
format fs=fat32 quick

With that said, I have yet to find a USB-stick that works and I now count eight USB-stick models that do not work. I hope others have better luck.
 
Shipped Friday late and my RMA was received today in Cali. 15-to 35 day turn around, so I guess the wait begins. Just wanted to tell people to try shipping FedEx, they were less than half the cost of other shippers. Almost had a stroke at UPS rates, upwards of $80.
 

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I gave up trying to flash with the BIOS button and got an EEPROM programmer instead. Worked fine and problem solved.
I got an CH341A and used this guide:
It was quite quick and easy, but it would have been even quicker and easier if the BIOS flash button had worked.

The BIOS chip is located here on the MEG Z490 Unify:
20220412_103124 (2)_LI.jpg
 
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I got an CH341A and used this guide:
One more video that does not explain CH341A sends 5V on data lines ... MX25L25673G used on MEG Z490 Unify is a 3V flash memory https://www.tme.eu/Document/1068b2ce565f5d3901bf372487b29d49/MX25L25673G, 3V, 256Mb, v1.4.pdf
There are some CH341A versions with an included switch for different voltages anyway I still was not able to find one in Europe (not that I am really searching for it).
Electronic components have tolerance anyway you supplied almost double the voltage to it; you were lucky.
All in all I wouldn't had give up with Flash BIOS button ...
 
One more video that does not explain CH341A sends 5V on data lines ... MX25L25673G used on MEG Z490 Unify is a 3V flash memory https://www.tme.eu/Document/1068b2ce565f5d3901bf372487b29d49/MX25L25673G, 3V, 256Mb, v1.4.pdf
There are some CH341A versions with an included switch for different voltages anyway I still was not able to find one in Europe (not that I am really searching for it).
Electronic components have tolerance anyway you supplied almost double the voltage to it; you were lucky.
All in all I wouldn't had give up with Flash BIOS button ...

Hm. Yes. Seems like I was lucky when using the CH341A. The PC works fine now, so atleast I were lucky with something.

I read the BIOS chip before programming it, and it was mostly blank. Seems the USB flash button prodecure had not written anything useful to it.

The current implementation of the Flash BIOS button needs to be fixed. When it is this extremely sensitive to using the correct USB storage device, I'm considering it broken. Besides the USB memory sticks pictured above, I borrowed another 8 different models, old and new, from friends. None of them worked. I spent many hours testing and hunting USB devices every day during two weeks.

I should have just tested the few USB devices I had at hand the first day, and then returned the board and let MSI know what I think about their implementation of the BIOS flash button.
 
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