Basically the title
At least a decade old, if not more than.
If you wanted to swap your vendor EFI image to something else, at this point it’s all going to be via a SPI programmer, and if you own one of the two boards that it supports, coreboot/openboot.
But, essentially, you can’t swap because there’s very little supported hardware, and thus are stuck with your vendor proprietary EFI.
What’s hilarious, I guess? is that the EFI setup is more or less it’s own OS that can then chainboot an OS which is how the mid90s workstations (Sun, SGI, HP, etc.) worked.
