Introduction
Whether you have a prebuilt system from a large vendor or a machine you built yourself from parts, you will probably need to update the BIOS at some point. Hardware vendors periodically release updated BIOS versions that correct problems or add new features. This post will cover Updating the BIOS on an MSI MAG B550 Tomahawk with M-Flash.
MSI has three main methods for doing BIOS updates. These include the M-Flash utility, using the Flash BIOS button, and using the MSI Dragon Center application from Windows. Of the three, M-Flash is the most common, and probably the most reliable.
Updating the BIOS with M-Flash
First, you will have to locate, download, and unzip the correct BIOS update file for your motherboard. Next, you have to copy the BIOS update file to a USB flash drive. Both USB 2.0 and USB 3.0 flash drives seem to work equally well. After that, make sure the USB flash drive is in a USB port, and then shut down and restart your system.
The M-Flash utility is in the BIOS setup program. During the POST process as your system is starting, you can press the Delete key to enter the BIOS setup program or you can press Ctrl + F5 to go directly into M-Flash. The M-Flash utility will read the BIOS update file from your USB flash drive and then update your BIOS. This typically takes around five minutes. When it is done, the system will shutdown and reboot.
I have a video that demonstrates this entire process.
One side effect of flashing your BIOS is that all the BIOS settings will go back to their default values. If you have made previous changes, such as enabling XMP, you will want to go back in and make those changes again.
AMD AGESA 1.2.0.1 Improvements
BIOS updates correct problems and they often introduce new features. For example, MSI has released a new beta BIOS version for all of their X570, B550, and A520 motherboards that includes AGESA version 1.2.0.1. This BIOS version enables Smart Access Memory for Ryzen 3000 Series CPUs and also includes a fix/improvement for L3 cache bandwidth performance in Ryzen 5000 series processors.
AIDA64 Cache Bandwidth Results
I ran the AIDA64 Cache and Memory benchmark on my MSI MAG B550 Tomahawk system before and after installing the latest BIOS update. There was a substantial improvement in L3 cache bandwidth, for reads, writes and copy operations.
Version | Read | Write | Copy |
1.2.0.0 | 281.09 GB/s | 279.39 GB/s | 294.67 GB/s |
1.2.0.1 | 462.38 GB/s | 466.0 GB/s | 443.02 GB/s |
Here are the results before the BIOS update.

Here are the results after the BIOS update.

Using the Flash BIOS Button
You can also use the Flash BIOS button to update the BIOS on this motherboard. It uses a different process that will often fix a failed BIOS update from another method. I have a YouTube video about how that works.
I also have a blog post.
Final Words
There is always some risk when you make any changes to a computer system. Updating to a new BIOS version is one of the more risky operations. It is possible for a BIOS update to fail, and possibly make your system inoperable. This is much less likely than it was years ago, but it can still happen. It has not happened to me in many, many years.
Being careful, following the instructions, and having your system protected by a UPS (in case you lose power during the update) will minimize the risk. Some hardware vendors have disclaimers about not updating the BIOS if your system is operating normally.
Personally, I think you will have fewer problems and have a better overall experience if you make an effort to keep your system BIOS up to date.
If you have any questions about this post, please ask me here in the comments or on Twitter. I am pretty active on Twitter as GlennAlanBerry. Thanks for reading!
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