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Rebooting machine whilst AVR/TV is turned off results in BIOS CSM error

Level 7

Hi there,

I have a high spec gaming PC which has been plagued with this problem from the start. Basically, when Windows Update does a restart in quiet hours, the machine never actually restarts. It seems to be in some weird hibernation mode with all the fans etc turned off, drawing almost no power, and with only the RGB showing on part of the motherboard.

When it is in this state it is impossible to turn back on. I have to pull out the power cable and then wait for the RGB to turn off, and then reconnect the power and turn on.

However, when I do turn the machine back on the BIOS halts with the following error


The VGA card is not supported by UEFI driver.

CSM (Compatibility Support Module) settings have been changed for better compatibility.

For further adjustments, press (F1] to enter BIOS setup.

If no adjustments needed, press [F2] to confirm the current settings and enter OS directly.

Press F1 to Run SETUP

Press F2 to Continue


I basically press F1, reload the saved bios profile, and then the computer will boot as normal and finish the Windows Update and load into Windows 10.

I later realised that this issue happens any time the machines is rebooted whilst the Marantz AVR is turned off. A shutdown and cold boot work fine, but a warm reboot with the AVR off always causes this issue.

I also realised that I could enable CSM in the BIOS and this will prevent the issue from occurring at all. However, it seems very odd I would need to do this, and CSM enabled seems to come with downsides such as a much lower resolution in the BIOS and during boot, 32 bit only firmware, and a less secure system.

Does anyone have any idea how I might be able to fix this issue whilst keeping CSM disabled?

Motherboard BIOS is fully up to date, so is Windows 10, and all drivers. This issue has been happening for nearly 3 years since day one of me building this machine.

Many thanks.


Customer Service Agent

Hello, @Pottypotsworth .

Does the situation you describe only happen during Windows Update and not in sleep mode?
Please help provide the following information so that we can better understand your situation:
- Is your current motherboard the ROG Crosshair VIII Hero, and the BIOS version is 4402?
- the brand and model name of the CPU, DRAM, GPU, and PSU currently installed
Meanwhile, please check the top right corner of the screen and kindly share the details requested in the PM inbox.

Thank you.

Hi there,

Thanks for the reply. Let me clarify a couple of points...

Here is the HDMI chain...

RTX3090 > Marantz 6012 AVR > LGE6 TV

- If I restart the machine whilst the AVR and TV are turned on, then the PC reboots fine
- If I shut down the machine whilst the AVR and TV are turned on, then the PC cold starts fine
- If I shut down the machine whilst the AVR and TV are turned OFF, then the PC cold starts fine
- If I restart the machine whilst the AVR and TV are turned OFF, then the PC reboots and halts on the CSM BIOS issue

Because Windows Update works in quiet hours, it is usually the middle of the night with the AVR etc turned off. Because of this, when Windows Update restarts the machine, I awaken to find it halted on the CSM BIOS error when I turn the AVR back on.

1) The motherboard is a ROG Crosshair VIII Hero (WiFi) and IS on the latest BIOS of 4402

2) AMD Ryzen 5900x,  G.Skill Trident Z RGB 32 GB (2 x 16 GB) DDR4-3600 CL16, Asus STRIX GAMING OC GeForce RTX 3090 24 GB, Asus ROG THOR 1200P 1200 W 80+ Platinum Certified Fully Modular ATX Power Supply

Since making my original post I have had a couple of interesting things happen.

A) Related to this problem: I noticed that when using DOCP it was setting the RAM at 3600, when it did this, the computer would not reboot coming out of the BIOS and I would have to pull the power and then cold boot the machine. I dropped the frequency down to 3400 and the computer did reboot correctly coming out of the BIOS. I then tried to reboot the machine from Windows with the AVR turned off (Which would uses cause the CSM halt as per my original post) but this time the computer rebooted fine. I suspect that the RAM frequency problem, coupled with the AVR being off was causing the CSM issue.
B) Not related to this problem: By sheer bad luck. It seems like my Ryzen 5900x is failing and as it stands right now, I can't even boot into Windows without a BSOD. I am currently in the process of trying to get this RMA's to AMD. Once this is done and the machine is stable. I can go back to troubleshooting this problem and re-testing my hypothesis that the RAM frequency set too high is the issue.


Customer Service Agent

Hello, @Pottypotsworth .

When you have the functional CPU installed, could you also provide us with the testing results in a scenario where the TV is not connected but a monitor is?
Please feel free to update us and provide any relevant information at any time.

Thank you.