Don't bother flashing a consumer motherboard for ECC.

Unlikely to work reliably, and even if it does, you’re risking a brick for marginal gain. Unless you already have a board with known modded BIOS support, skip it.

The Xeon E3-1231 v3 can use unbuffered ECC, but consumer chipsets (H81, B85, H87, Z87, Z97) don’t support it officially. Some boards have the traces and memory controller routing but hide ECC in BIOS. Enthusiasts have modded ASUS and Gigabyte BIOS files to unhide those options.

The effort is moderate: find the right mod for your exact motherboard revision, flash using USB or SPI programmer, and pray nothing goes wrong. Success depends on board layout. Most consumer boards just don’t have the wiring for ECC, so even with a modded BIOS, it won’t work.

Unless you’re already comfortable with BIOS modding and have a specific board known to work (e.g., some ASUS H87 boards), the time and risk outweigh the benefit. Just get a proper C226 or C222 board if you really need ECC.

Your time is better spent on something that actually works.