Thinkpad L13 G4, AMD - 21FQ

[kitor]

L13 G4, AMD - 21FQ-S04R00 / PW-067ZHK
Powers on, no image. Fans do spin when heated up, power button long press works to shut down and then press to start unit again.
No keyboard led blinking (except just a normal 1sec ESC/F1/F4 leds right after power button press).

What I already tried:
- extracted Lenovo update. .FL2 file contains EC image that appears twice in EC dump (similar to Yoga variant described here), i replaced both. No change in behaviour
- Truncated .FL1 file from the extra header and cut down to BIOS flash size (comparing in hex editor data aligns perfectly). Also no change. But possibly some sections of the original needs to be transferred over?

After flashing one extracted from .FL1 and failed boot I dumped BIOS again and saw differences so machine is definitely executing code...
Thermal imaging shows nothing suspicious.

Original BIOS dump when put into UefiTool complains about "not a single Volume Top File is found, image may be corrupted".
One extracted from .FL1 file parsed fine.

I attached both dumps (16M EC and 32M bios).

[SMDFlea]

Try this main bios. Flash the 16MB backup bios back as-is.

[kitor]

Hey,
Thank you! Sadly, no change in behaviour - still reacts to power button, does that "normal" ESC/F1/F4 leds power on/off and fan works (+ by the coil whine you can tell it is doing something )
I left the laptop in this "running" state for a good couple of minutes and thermal imaging shows nothing weird, all voltage rails are there.
For a moment I thought I have the "gotcha" moment - while looking under a microscope found a suspicious dot on EC but it turned out to be just a splash of the chip underfill, not the magic smoke exit point.

[SMDFlea]

Hey,
Thank you! Sadly, no change in behaviour - still reacts to power button, does that "normal" ESC/F1/F4 leds power on/off and fan works (+ by the coil whine you can tell it is doing something )
I left the laptop in this "running" state for a good couple of minutes and thermal imaging shows nothing weird, all voltage rails are there.
For a moment I thought I have the "gotcha" moment - while looking under a microscope found a suspicious dot on EC but it turned out to be just a splash of the chip underfill, not the magic smoke exit point.

try this 16MB backup bios with the new EC from the FL2.

[kitor]

Tested with the main bios you provided previously, still no change.