You can't sign your custom kernel, only Windows can be signed and signing has to be disabled for Linux and other OS. UEFI offers some basic IO functionality, i

You can't sign your custom kernel, only Windows can be signed and signing has to be disabled for Linux and other OS. UEFI offers some basic IO functionality, it's like BIOS in that regard. You don't design your OS around it, you use it to have easy graphics, networking etc during boot time, then you switch to your own drivers and don't touch UEFI again.