Checksum CMOS 502 error possibly related to non HP battery

[tslav]

I have scoured the forums and general internet for CMOS 502 checksum errors and probably have tried dozens of potential fixes non of which has solved the problem. I'm curios to know if this boils down to the CMOS not being compatible with non HP notebook batteries? That seems to be the only reason I see the CMOS error consistently re-appearing and the only thing I have been able to test not having or wanting to buy another new battery. Basically now I want to know if having non HP batteries will always cause a CMOS checksum error? This could save me or potentially anyone else from trying any fixes for this error if the solution is that an HP battery must be used. 

Here is the summary of the issue as there are many posts about this and the many different solutions posted out there which haven't worked. I will receive a CMOS 502 checksum error after the notebook as been on battery power for sometime. Usually works fine to sleep or reboot on battery power, however without fail it will cause the error on one of those startup attempts or wake from sleep. 

- Notebook is a HP Omen 15-dc0025 which does not have its own CMOS battery but draws power from the main battery to hold CMOS settings. Usual suggestion is to change the CMOS battery, not possible here

-Next most popular solution is to upgrade or repair/recover the BIOS. Several issues here, first is that this model of Omen does not officially support Windows 11 therefore any tool or bios upgrade is not available for Windows 11 for this computer. I did successfully upgrade the bios from a previous older version for s slightly newer version from 2020 however there is nothing past that available to install. Secondly it is not clear that the recovery does anything as there is no log for BIOS resets and if anything has happened. 

Thanks. 

[Nal_NR]

Hi @tslav,

Welcome to the HP Support Community. 

I'd be happy to help you! 

I understand that you are having issues with the Checksum CMOS 502 error.

Fabulous analysis. Spectacular diagnosis of the issue before posting. Kudos to you for that.

If you have tried all the steps from this document and the issue still persists, I recommend you contact phone support.

For that to happen, we will give you additional instructions/information via Private Message.

Please check your inbox on the forums page for the private message.

Please mark this post as “Accepted Solution” if the issue is resolved and if you feel this reply was helpful click “Yes”.