What is .cap?

• Since some update, all ASUS BIOS files must be in .cap format instead of .rom format
• .cap format is raw .rom format with 2048 bytes header prepended
• The header is likely to be some sort of cryptographic signature and/or checksum
• EZ flash check this header, while BIOS flashback does not

My case

• Z10PE-D8 WS BIOS, 3407
• Haswell microcode removed
• me_cleaner with -S option applied
• Original 3407 .cap header is prepended into the modded .rom, it became the file below
• Rename the file downloaded to Z10PEWS.CAP and put it into root of FAT32 USB drive, start BIOS flashback, success for me. https://drop.wtako.net/file/9321f82f97bc7a7b84b1fb0d76d3c3b10cc0a92f.CAP

.cap to .rom?

$ dd if=Z10PE-D8-WS-ASUS-3304.CAP of=Z10PE-D8-WS-ASUS-3304.rom bs=1024 skip=2 as mentioned in https://github.com/corna/me_cleaner/issues/71 Just remove the first 2048 bytes.

.rom to .cap?

Since .cap is signed and EZ flash checks it, it is NOT possible to flash a modded .cap unless you know how is it signed.

But, if your motherboard supports BIOS flashback

1. $ head -c 2048 Z10PE-D8-WS-ASUS-3407.CAP > modded.cap
2. $ echo your-modded.rom >> modded.cap
3. $ mv modded.cap MB_CAPNAME.CAP
4. You can now flash the .cap you made. For names and method please refer to https://www.asus.com/support/FAQ/1013998/.