Blackout screen ( 502 BIOS/ CMOS reset)

[WhosAR]

Hello, I have this issue where my laptop suddenly powered off and didn't turn on again. I charged it and a black screen came up, I looked up tutorials on how to fix it and when I did the tutorial, it worked for a split second but it was just another black screen telling me that the issue was with the Bios/ CMOS, So I try to update the bios by grabbing another laptop and a hard drive but there is no bios listed on the software help page for my OS version. I'm confused on how I'm supposed to fix this issue if there is no bios listed at all. 

[Jerry_57]

Hi @WhosAR,

Welcome to the HP Support Community.

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

I hear that error 502 means “CMOS Recovery Occurred.” HP states this message indicates the CMOS recovery completed successfully, and no further action is required for that specific code. If the system still shows a black screen or will not boot, the issue may be elsewhere in the startup process.
 

What HP recommends:

• Perform a hard reset:
  
  
  1. Turn off the computer.
      
  2. Disconnect all external devices.
      
  3. Unplug AC power.
      
  4. Disconnect/remove the battery if possible.
      
  5. Press and hold the power button for at least 15 seconds.
      
  6. Reconnect the battery and the AC adapter only.
      
  7. Turn the notebook on.
      
• Reset BIOS to default settings:
  
  
  • Restart and press F10 > Main > Restore defaults.
     
• Run HP PC Hardware Diagnostics (UEFI):
  
  
  • Turn on/restart the PC, press Esc, then F2.
     
  • Run available tests to check hardware.
     
• Check/reseat connections if serviceable:
  
  
  • HP notes that loose connections can cause boot problems.
     
• If you saw a BIOS-related message after recovery, HP also notes that error 501 means the BIOS installation may be corrupted, and the recommended action is to download and install the latest BIOS.

Important note about BIOS downloads:
 

If the HP Software/Drivers page does not list a BIOS for your OS version, I don’t see a source here that confirms an alternate BIOS package by OS workaround. From the provided HP content, I can only say:
 

• use the latest BIOS/driver updates when available,
   
• And use HP PC Hardware Diagnostics plus hard reset / BIOS defaults first.

I hope this will help.

 

Take care and have a good day.