E6420 BIOS updated failed - bricked notebook?

Hi,

An attempt to upgrade BIOS of E6420 failed. Now the notebook doesn't boot.

No POST, fans doesn't spin, no lights, nothing. It is completely dead.

The only thing it does: The Power indicator LED on the back side of the lid is glowing white and blinks once every 5 seconds. None of the LED works if you open the lid. Only that one on the outside of the notebook.

I have tried the usual things, including

- Remove battery and power cable and push the power button for 30-60 sec

- Dismantle notebook - remove BIOS battery, RAMs, wifi card etc

- Attempt to use BIOS recovery. Remove battery and power cable and try pushing Fn B, Esc, End etc and reconnect power cord.

- I tried creating a Wincrisis USB however, I'm having problems to extract ROM file from the .exe file. /writeromfile doesn't seem to work.

Any suggestion is welcomed!

Thanks in advance

Gabor