Hi sir, can you please help me out? I'd be very grateful!...

Sadly I had another mishap with another G4 820.
I have included dumps of BIOS and EC ROMs

I would be very grateful if this machine could be restored.
...

I have ordered and received new Winbond chips for both the BIOS and EC, and reflashed them with the files in this thread.
No improvement yet so it is not that I broke the chips with temperature.

Can someone please double check the files? Maybe the BIOS got partially repaired by the EC (SureStart) but become damaged, then the EC got corrupted by the damaged BIOS?

Thank you. No improvements however - charging LED keeps blinking, with an extremely short blip of the power LED.
Managed to fan spin once, but it went to max speed. No video or even impression of backlight turning on.
Now it just it won't fanspin even and keeps at white/orange blinking

I don't know how to proceed. I would not suspect hardware issues because the computer worked fine initially until I rebooted it after setting custom Secure Boot keys in Linux

Thank you. Sadly, no improvements are noticed.
I have included a dump of the EC....

Hi hoaca388, thank you for your reply, please see my answers in italic below:

You MUST:

• Read BIOS guides, methods, resources and tools
  • I have read this (very well written) guide and used it up to get to this point where I get stuck
• Try the method at BIOS guides, methods, resources and tools before requesting help
  • I have tried the methods in this (very well written) guide and used it up to get to this point
• Explain you were not able to succeed with the methods at BIOS guides, methods, resources and tools
  • I have succeeded with the methods in that (very well written) guide

...

Hi guys,

If someone would be able to provide some expertise, I'd be very grateful.

BIOS Corruption - Cause
So I managed to corrupt my machine by installing linux and enrolling custom secure boot keys. I did choose to enroll the Microsoft keys as well, to prevent any potential bricking due to 3rd party drivers from HP being signed with those keys.
After doing that, and rebooting(it did boot, powerLED, fanspin etc.), the laptop did not give any video output on the LCD or video connectors. I think I was able to get in BIOS and trigger the beeper by pressing ESC....