Just so happened to be fiddling with the uefi-rs crate too today. So if I understand this correctly, Patina is the part that runs on the hardware side, ie, the firmware? Uefi-rs based on what I read/tried seems to be the software side, building apps that work before the OS is loaded (I assume for things such as boot loader, firmware updaters, etc) but I'm not sure if it also covers the hardware side