HP Elitebook 840 G6 won't power on after BIOS update. Caps/numlock flashes 7 times.

[ikethedergon]

Recently got a lot of untested laptops for cheap, one was an Elitebook 840 G6 it worked after I put RAM and an SSD in it but now after a BIOS update to the latest version it will no longer power on properly it just has 7 flashes from the caps/num lock key lights.

[Jupitero]

Hello.

Does the blink pattern correspond to any of the blink codes listed here:

HP Notebook PCs - Computer beeps or a light blinks during startup

[ikethedergon]

I'll upload the video I took of it.

https://youtube.com/shorts/LfVE31ez86E?si=jOkdN1N4J7OsmyPj

[Jupitero]

Hello again.

CAP/NUM Blink = 7 sequence indicates "The embedded controller cannot find valid firmware", and the way to correct this problem is System board replacement.

Blink lights for your laptop are explained in the the Maintenance and Service Guide for 840 G6, page 81, Part 7, "Interpreting system validation diagnostic front panel LEDs and audible codes."

You can take the laptop to a local HP service partner or a generic computer/laptop repair shop and have them quote you a replacement. That same PDF guide includes all the system board models available for 840 G6, and you can at this point change to a better CPU model as well. Moving from UMA to discrete graphics - or vice versa - requires also replacing the heat sink and moving to 65W charger. You can replace the system board by yourself, but I don't recommend it unless you already have some experience working with laptop internals.