Nicelly done, correct volume insertion and no pad files removed, a pad is present in the original and mod, flash it only with M-Flash, NOT OS environment.
But before, i suggest you do a backup of the current system bios as it contains its own motherboard original data, FPT8 tool as cmd line: FPT -d fullSPI.bin or FPT -bios -d biosREG.bin
Or other familiar tools to you.
3. Flashing of the modded BIOS RISKS and WARNING
For correct UEFI NVMe OS install return to linked guide.
Good luck.
EDIT: Glad to hear it, enjoy it, and tank you for sharing.