This is super cool. Had no idea UEFI APIs were so readily-available and well-documented. Awesome work! Out of curiosity, what was the dev cycle like? I assume you were running the thing in a VM. Did you have to "boot up" every time you wanted to run the client?
The other commenter is correct that the work loop typically revolved around booting a QEMU instance which ships my UEFI application. The main run script will regenerate an EFI filesystem that contains a fresh build of UEFIRC, then pass it to QEMU.
However, the overhead here can get a bit cumbersome when trying to build a GUI. I set things up such that the app could target either bare-bones UEFI, or a hosted environment that runs on my Mac. By flipping a build flag, my GUI toolkit would either draw directly to the UEFI-provided framebuffer, or would hook into my Mac's windowing system and receive/push events to that. You can see some of the overhead of this 'dual-target' approach in the app's entry point: https://github.com/codyd51/uefirc/blob/main/src/main.rs.
