Many OEM .exe files contain a raw BIOS image.
This is the cleanest method. Many .exe BIOS files are actually self-extracting archives (SFX), similar to a .zip file. bios exe to bin file converter
If you need to convert a BIOS .exe to a .bin , do not look for a single "magic converter" program. Instead, follow this hierarchy of success: Many OEM
binwalk extracted.bin