Changing serial number in Lenovo InsydeH20 Bios

[Andy78]

Hi everybody,
 
I changed the mainboard of my Lenovo IdeaCentre A540.
The new mainboard works so far, but the error “00CE: Machine Type and Serial Number are invalid” appears during boot-up.
 
Bios: InsydeH20
Bios Revision Level: O00KT18AUS
Boot Block Revision Level: 1.18
Bios Build Data: 08/15/2014
Microarchitecture: Haswell
 
I have already spent a lot of time to solve the issue (Lenovo Maintenance Disk, DMI Editor etc.), but without any success. Lenovo doesn’t provide any update for my Bios version.
 
When reading similar posts in this forum, I basically recognized three possibilities:

1. Unlocking InsydeH20 Advanced Settings
   
2. Changing variables via an UEFI Variable Editor
   
3. Updating Bios with a modified version
   

 
Has anybody experience on how to enter the serial number and could provide any advice?
 
Would be more than happy for any support.