[REQUEST] Please help me do an nvme mod the Asus H81m-C bios

I tried and failed to understand how to deal with .CAP bios files, could someone help guide me or mod this bios for me? thanks.

CAP is Asus secure header… depending on overall operations (mod/flash), mods can be done or not in CAP files or extracted bios image without CAPSULE.
Motherboards without USB BFB cant use CAP mods.
For reading: [Guide] How to flash a modded AMI UEFI BIOS - BIOS/UEFI Modding / BIOS Modding Guides and Problems - Win-Raid Forum (level1techs.com)
Explain your mod intentions on the mod needed.

I want to be able to boot off of an nvme drive
And yeah I did try, got as far as this

Seems that you dont like to read or skipped important details, read it again (the 2 guides) and do not skip any detail, thats what kills a man…
[HowTo] Get full NVMe support for all Systems with an AMI UEFI BIOS - Special Topics / NVMe Support for old Systems - Win-Raid Forum (level1techs.com)
The error you got its correct, because it seems you didnt pay attention to what i wrote about Asus bios.

*A current backup/dump of the system bios is a MUST for recover methods and risks of fail flash, that can break the system, as is all over the forum written.