That means with 100% certainty that he tried exactly that. In PC repair you learn that you can take the customers word with very little creed.
Sounds like he either got a bad file, bad USB stick, or messed with the system during the flash. Shame is I can't remember the last socketed BIOS chip on a laptop I have seen... what model laptop is it? And as @TempestCatto said, have you just loaded a file on a FAT32 formatted USB stick to see what happens? I honestly doubt it'd work, but laptops are very strange.