Support: Possible to re-sign secureboot and then chain boot other ISOs?

[gcb]

I have some systems with windows secureboot keys and others with custom key.

So the first question is if i can simply sign the EFI file with the custom key too?

Then does the grub2 boot process, after booting into secureboot, allow to boot a non secureboot (e.g. arch install ISO) from that point on?

thanks!