Question CSM Settings In BIOS Keep Resetting

System32_76

Prominent
Jul 29, 2019
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2
535
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Hello!

Whenever I start up my computer, the settings under CSM (Compatibility Support Module) under my BIOS keep resetting back to "Legacy Only" even though I manually set CSM to be disabled.
View: https://imgur.com/CJjIp61


I replaced the CMOS battery that came with the motherboard with a new one but that didn't change anything at all.

What could be the cause?
 

Darkbreeze

Retired Mod
What are your full hardware specifications including exact model or series numbers for CPU, motherboard, memory kit, graphics card, power supply and any other add in cards that might be installed in any of the motherboard PCI slots?

Are your keyboard and mouse both USB type devices and are the batteries fairly new in those?

Is secure boot enabled or disabled?

What is the first boot device set to? Windows boot manager OR some specific drive?
 

System32_76

Prominent
Jul 29, 2019
75
2
535
0
What are your full hardware specifications including exact model or series numbers for CPU, motherboard, memory kit, graphics card, power supply and any other add in cards that might be installed in any of the motherboard PCI slots?

Are your keyboard and mouse both USB type devices and are the batteries fairly new in those?

Is secure boot enabled or disabled?

What is the first boot device set to? Windows boot manager OR some specific drive?
Here are my specs:

Motherboard: AsRock Z97 Anniversary
CPU: Intel i5-4590 @3.3Ghz
GPU: Gigabyte Geforce GTX 1050 Ti (not sure what exact model it is)
RAM: 2x4GB Corsair Vengeance RAM and some other 2x4GB RAM (brand unknown)
HDD: WD Blue 1TB 10EZEX
PSU: Corsair CX500M (500 Watts)

I'm also using a PS/2 keyboard and wired USB mouse, secure boot is disabled, and the first boot device set to is "ubuntu" since I'm running Ubuntu Studio 20.04 LTS.
 

Darkbreeze

Retired Mod
CSM cannot be disabled and still use a PS2 keyboard. In fact, even some older USB devices will require CSM to be enabled. You MUST have ALL UEFI compliant hardware including peripherals that are connected, in most cases, especially if those peripherals are required for the POST process error checking, by USB.

What you CAN try to do to see if it will work as a band aid, is to go into the BIOS and disable the following two options if they are present, and they ARE for most modern motherboards from the last six years at least.

One, disable the option for the system to stop on error if no keyboard is detected.

Two, in cases where it is an older USB legacy device that is causing the problem, you can change the option for "full USB initialization during POST" to "partial USB initialization during POST". That will SOMETIMES resolve some issues of legacy devices during the POST process and allow the drivers for those devices to simply load once Windows or other OS environment takes over the boot process.

Otherwise, you need to either leave CSM enabled or get a newer keyboard that is fully UEFI compliant, so at least USB 2.0. Same goes for any other USB devices that are older legacy type hardware, or add in cards as well that are legacy non-UEFI.

The fact that it's Ubuntu doesn't really matter until after it has cleared the POST process environment.

I honestly doubt there is any work around for this so long as you are using a PS2 keyboard or other device though. That is absolutely a "legacy" device, and it cannot be supported by the UEFI boot environment.
 

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