A quick guide is kind of funny… I can tell you how i did it. (Based on Hodins great work and discovery. Thanks again, Hodin!)
You need a clean FAT32 formatted USB stick with not more than 8GB. Laptop should be fully charged and connected to charger.
Make sure your Bios is a v5!!! (You can check that with HWinfo for example.) v5 is build 11/06/17 Bios Tag 3BANS010. Even better would be to check your Bios dump with AMIBCP. Also check the v4 Bios if it’s the right one! Both versions should be Bios Tag 3BANS010!!!
Make a copy of your current Bios and store it on the USB stick. Rename it to v5. (I used AFUWINGUIx64 for that.) It’s save to do it out of Windows. IMPORTANT! Do NOT use AFUWIN to flash the Bios out of Windows!!!
Now you need a valid copy of a v4 Bios. Rename it to v4 and put it on the stick. v4 is build 08/07/17 Bios Tag 3BANS010.
Look for AfuEfi64, extract it if packed and put all files without folder on the stick.
Now restart the Laptop and switch to Bios. Go to Boot Menue and select “Build in EFI shell”.
In efi shell, switch to the usb stick and check directory to make sure.
Now you can start the flashing process with the command: AfuEfix64.efi v4.rom /P /B
Let it do its work…
After flashing is finished, exit efi shell to Bios and restart.
Let it load into windows, than power off.
After the restart, Bios v4 should work.
IMPORTANT!
I’m not responsible if you damage your Laptop!
Flashing only works from v5 down to v4 at the moment.
You may want to wait with flashing based on this guide till another expirienced user confirmed all steps.
You may want to wait another day or 2 if Giovanni can find a rather save way to unlock Bios!
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Anyway it was a good exp. So, if no success with restoring on programmer – my daughter will have a nice-looking toy (after batteries removal) :)))
