BIOS Settings Reset After Boot: CSM and Resize BAR Issues

[Aldebaran]

Every time I boot my PC, the BIOS settings revert to default. After changing the BIOS settings (disabling CSM, enabling 4G Decoding and Resize BAR), I save and exit. AMD Adrenalin then shows that Resize BAR is enabled. However, after the second boot, Resize BAR is disabled again, and CSM is re-enabled by default. AMD Adrenalin shows that Resize BAR is disabled. I've tried multiple times (disabling CSM, enabling 4G Decoding and Resize BAR) and saving, but it always returns to default after the first boot, and by the second boot

Motherboard: asrock b450m pro4-f

 

[Ruru]

First gen Ryzens doesn't support it AFAIK.

 

[RJARRRPCGP]

Resizable-BAR is irrelevant with GCN.

And, that behavior, if using Windows 11, likely will result in Windows 11 locking you out! Possibly 10, if using a Microsoft account as well.

I suggest changing the CR2032 battery!

 

[Bill_Bright]

I suggest changing the CR2032 battery!

^^^THIS^^^

The CMOS battery has two jobs. (1) Keep the RTC (real time clock) ticking (counting) and (2) preserve user changes to the BIOS Setup Menu stored in the CMOS device when power is removed from the system.

Typically, these batteries, when used in motherboards, easily last longer than the user keeps the motherboard. But I have seen them fail in 1 or 2 years, and have even received brand new DOA batteries.

Go buy a new one. They are inexpensive. Power off the computer AND unplug it from the wall. Touch bare metal of the case interior to discharge any static in your body. Note the polarity (physical orientation) of the old battery, then carefully remove the old battery. Do NOT touch the new battery with your bare fingers - skin oils promote corrosion and attract dust. I put a clean sock over my hand. Touch bare metal with your bare hand again and insert the new battery, observing properly polarity, with the socked hand.

While in there, double check all your cables to ensure they are securely fastened. Make sure the interior is clean of heat trapping dust. Then connect power and boot directly into the BIOS Setup Menu. Check/reset the clock and any other user changes you need, then Save and Exit to [hopefully] boot normally.

 

[Aldebaran]

^^^THIS^^^

The CMOS battery has two jobs. (1) Keep the RTC (real time clock) ticking (counting) and (2) preserve user changes to the BIOS Setup Menu stored in the CMOS device when power is removed from the system.

Typically, these batteries, when used in motherboards, easily last longer than the user keeps the motherboard. But I have seen them fail in 1 or 2 years, and have even received brand new DOA batteries.

Go buy a new one. They are inexpensive. Power off the computer AND unplug it from the wall. Touch bare metal of the case interior to discharge any static in your body. Note the polarity (physical orientation) of the old battery, then carefully remove the old battery. Do NOT touch the new battery with your bare fingers - skin oils promote corrosion and attract dust. I put a clean sock over my hand. Touch bare metal with your bare hand again and insert the new battery, observing properly polarity, with the socked hand.

While in there, double check all your cables to ensure they are securely fastened. Make sure the interior is clean of heat trapping dust. Then connect power and boot directly into the BIOS Setup Menu. Check/reset the clock and any other user changes you need, then Save and Exit to [hopefully] boot normally.

Thanks,Bill_Bright! I really appreciate your detailed explanation and advice.

 

[RJARRRPCGP]

And, that's why old motherboards from decades ago, have a battery. Fun fact, I had a 1990s 486 system with a motherboard using double-A batteries, in the very-late-1990s and the very-early 2000s.

Of course, being a 486, it was from the "504 MB BIOS limitation" era. (later-pre-LBA)

 

[Bill_Bright]

And, that's why old motherboards from decades ago, have a battery.

Huh? Is that what you meant to say? I note new motherboards from today have a battery too.

 

[ShrimpBrime]

Disable secure boot for CSM enabled.

Unless there is legacy hardware plugged into the board, maybe Sata II HDDs for example, may force the board into CSM mode.

If the battery was bad, it would not save the date time. That's one way to tell if it needs to be replaced. Can also view the output of the battery on most boards in the voltage and temp monitoring section of the bios. If that battery reads less than 3v, it should be replaced.

GLHF!

 

[RJARRRPCGP]

Huh? Is that what you meant to say?

All motherboards have a battery for storing the selected BIOS settings. Back in the 1990s and before that, CR2032 didn't seem to be all a standard. By the very-late-1990s, CR2032 seemed to have taken place of the other battery styles.

 

[Bill_Bright]

All motherboards have a battery for storing the selected BIOS settings. Back in the 1990s and before that, CR2032 didn't seem to be all a standard. By the very-late-1990s, CR2032 seemed to have taken place of the other battery styles.

Right. Your original statement suggested only older motherboards had batteries. The facts are, new motherboards do too. Thanks for clarifying.

Ever since motherboards started using CMOS memory devices (and later, CMOS circuits) to store user changes to the BIOS Setup Menu, they used batteries to provide the necessary "holding voltage" on those devices to ensure the stored data was not purged when power from the power supply was removed.

Early motherboards did use a different type of battery, primarily because early button batteries were very expensive and contained much more mercury than they do today. Still, do note button cell batteries such as the CR2032 commonly used on motherboards today, should be properly disposed of at battery recycling centers and NOT thrown in the trash. This is because most still contain some mercury. Lithium is hazardous to the environment too.