Elitebook 840 G6 Blink Codes --after Update

[Joegrane]

Hello,  this laptop had a firmware update in the list of optional Windows updates.   After download I restarted the laptop when prompted.   It choked on the update.  I saw some type of firmware update error message but did not document it : (

I decided to go ahead with a manual upgrade to Windows 11 using the Rufus method which I've done successfully a dozen times.    At some point during a reboot the computer would not make it through POST.  

After inserting the power cord a white LED is lit on the Caps Lock button.  There is 1 brief blink, maybe every 5 seconds or so. 

I opened the back cover, disconnected the main battery.  

I then disconnected Ram and M.2 SSD.  

I then disconnected  CMOS battery for 20 seconds and reassembled everything. 

The problem persists. 

Any leads?   

Thanks

Joe

( I am a tech pro and have previously used HP's offline troubleshooting from a USB thumb drive. )

[Joegrane]

The description seemingly matching what I see is the following from a maintenance doc on HP's site. 

System Board 5.3.   The embedded controller has timed out waiting for the Bios.  Cap/Num Blink = 1.   Action: System Board Replacement. 

Does that make sense based on my description above?

[TzortzisG]

Hello Joegrane.

Unfortunately, HP at some point started pushing BIOS updates through Windows Update. Although in most cases the automatic procedure of flashing the BIOS chip with the new firmware will go as intended, occasionally the update gets botched and the result is a "dead" machine with a black screen, a screaming fan and various led lights blinking. Statistically speaking, I think one should assume that the BIOS is corrupted UNLESS proven otherwise. You can also look at the HP document that explains the various aspects of the BIOS on Business laptops (and includes the G6 models) here. Page 53 lists the Blink codes.

System board replacement is just HP's way of dealing with these issues. Nowadays most users just reflash the UEFI firmware externally (or have it done at a chip-level repair facility that works with motherboards).

[Joegrane]

Thank you : (