There are couple ways. You can compile UEFI for QEMU (OVMF package or possibly compile coreboot with Tianocore payload). Another way is just output. UEFI gives

There are couple ways. You can compile UEFI for QEMU (OVMF package or possibly compile coreboot with Tianocore payload). Another way is just output. UEFI gives you shell, so you can see output and in UEFI it's much easier to deal with this stuff. If you use coreboot and libpayload it's much easier because it offers you built-in GDB server you can connect to via serial port.