Cmos reset 502 error

[Sumoneunknown0]

Cmos checksum error 502 screen pops up over and over hit windoes +b and a screen pops up saying to insert usb to recover bios then restart computer but nothing happens when i do this.

[Sneha_01]

Hi @Sumoneunknown0,

Welcome to HP Support Community.

Thank you for posting your query, I will be glad to help you.

The CMOS checksum error 502 indicates that your laptop's BIOS settings have been corrupted or lost. This often happens due to a drained or faulty CMOS battery. Here are the steps to resolve this issue:

1. Perform a Hard Reset:

• Unplug the laptop from the power adapter.:
  • Disconnect any external devices.
  • Press and hold the power button for about 15 seconds to ensure all power is drained.:
  • Plug the laptop back into the power adapter.:
  • Press the power button to turn the laptop back on.

BIOS Recovery Using USB

Since you mentioned that pressing Windows + B asks for a USB to recover the BIOS, here’s how to create and use a BIOS recovery USB drive:

1. Download BIOS Recovery Files:
   • On another computer, go to the HP support website and download the latest BIOS update for your specific laptop model.
2. Create a BIOS Recovery USB Drive:
   • Follow the instructions provided on the HP support website to create a bootable USB drive with the BIOS recovery files.
3. Insert the USB Drive:
   • Insert the USB drive into the affected laptop.
4. Initiate BIOS Recovery:
   • Press and hold the Windows + B keys, then press and hold the power button for 2-3 seconds.
   • Release the power button but continue to hold the Windows + B keys until the BIOS update screen appears.
5. Follow On-Screen Instructions:
   • Follow the instructions to recover the BIOS. This process may take several minutes.

I hope this helps.

Take care and have a good day.

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

Rachel571

HP Support