EFI password in x86 Android Tablet

[Bim]

Hi Forum.

I have this Android BayTrail x86 tablet (Medion LifeTab P8314 / MD99612) I wanted to install Linux or a newer Android to. To boot Linux from an USB stick I wanted to change the boot order, but I can not access the EFI setup. Normally the setup can not be accessed, but booting from a Android-x86 LiveUSB-Stick gave me the option to enter the EFI setup. When I chose this, a BIOS-setup-like text screen appears and wants me to input a password, supposedly to enter the BIOS setup. Is there a way to disable that by modding the ROM?
I have extracted the AMI BIOS ROM (see attachment) using AfuEfix64.efi. I can open that file in AMIBCP 5.01, but got no idea where to search...
I also tried reflashing the ROM with AfuEfix64.efi and setting some options to clear the NVRAM, but the password does not seem to be stored in the NVRAM...

Any hints on removing that password are welcome. I'm not afraid to break the device, so hack away...