[SOLVED] MSI B550M Mortar - Bios Flash/boot issues

[Pijus_]

Hey all,

I made a build with B550m mortar wifi + Ryzen 5800x. It booted into bios on the first try, however, after reducing fan speeds in bios and saving the settings, the system stopped booting/posting. I get a red cpu debug led on.

Issue really seems to be bios related, so I have tried many things, including:

• Resetting CMOS by removing the battery and disconnecting PSU cables for 10+ minutes. No effect.
• Resetting CMOS by shorting the JBAT1 pins. No effect.
• Flashing new BIOS through USB with all parts connected. This did not work, the Flash BIOS light keeps blinking fast forever (tried it for 30+ minutes, motherboard debug CPU light is red). System turns on a few seconds after pressing the flash bios button, all fans are spinning, but the process never ends.
• I removed all the components and only left the PSU connected to CPU and ATX power ports. Then tried flashing BIOS again. Now, the Flash BIOS light is blinking slow (3s intervals), but also seems to go on forever. There is no motherboard debug lights on.
• I got my hands on Ryzen 3900x and tried the same processes. System does not post, CPU debug led is still on when powering the system up. CPU fan does not turn on. Flash BIOS does not work - led is blinking slow and forever (left overnight, was still blinking in the morning)
• I tried 4-5 different USB drives (8/16GB), tried formatting with Windows format feature, as well as using Rufus and also on Mac. FAT32, MBR, seem to have tried all the suggested methods from various threads online.
• Also tried at least 4 different BIOS versions, makes no difference.

I have spent a crazy amount of hours reading up online and trying to fix the issue. At this point I am pretty much giving up and considering getting a replacement. Is my board faulty? Did I mess it up? Are there any other things I could try? Please help

 

[Lutfij]

The thing with BIOS flashing, is, you need to be patient. There were times I've had to wait nearly 2 hours for a flash to go right. If you're impatient, then it's possible you can botch up the update and the BIOS chip and end up with a bricked motherboard.

Look through page 48, on your manual, and follow the steps outlined, you don't need RUFUS to deal with the pen drive, just a donor system(non-Mac) that will allow you to use formatting.

Lastly, you seem to be blaming the motherboard...I'm yet wondering what the rest of your specs are

 

[Pijus_]

I have left it overnight to complete the flash and it the led was still blinking in the morning, so I feel like I am being patient enough. I am also attempting to do it again right now, it's been over an hour. I don't expect anything would change.

I have followed the standard guide, as well as many different alternatives suggested by people fighting with similar issues, nothing seems to work. From all the threads I read online about the issue, it seems to be a rather common problem.

Here is my complete build: https://pcpartpicker.com/list/x7Xh7X

 

[NeedMoarToys]

For what it's worth. I had the exact same issue. MSI B550M mortar NON-Wifi, ryzen 7 5800x. Boots into BIOS first time, enable XMP and fan curve, then it doesn't boot. Initially the debug LED was stuck on VGA then it eventually got stuck on CPU. I'm using 79C14 btw, the latest NON-BETA bios.

I removed CMOS battery for 10 mins with system completely shut down and unplugged with keyboard mouse and monitor the only peripherals on board. After reinstalling CMOS battery It booted into BIOS and then I was able to change windows to boot CSM (because I'm using all m.2 storage), and I am typing right now from a successfully booted 5800x on B550M mortar.

It appears this BIOS is absolute garbage and will not allow the user to change basically anything. Lucky thing I have a B550m TUF I received in a bundle. My experience with MSI software has been...rough.
On the plus side, it appears my 5700XT is now passively cooled by the gale force winds coming from my 3 120mm fans in the front.

I will contact MSI tomorrow to see if they are aware of these issues. I've never had a system that won't allow custom fan curve or be reliable with XMP. It makes sense they would flash their bios on a test bench, get into windows with base settings, and call it good.