H97-HD3 1.2V+ Vcore unlock

[Kulturnilpferd]

Hey there,
I have a H97-HD3 with a i7 4790k. The problem is that I can't go higher than 1.2V in Bios settings. When I patch the last Bios version from Gigabyte the Vcore is set default to 1.25V but when I change something after the update the vcore is back to 1.2V. Is there a chance to modify the bios to disable or change the max. Vcore in the Bios file with hex editor from 1.2 to 1.3+ Volt? I have tried it with the Gigabyte OC tool (have modified the xml profile) but these doesn't seem to work also due internal software limits...