How to Open oem.BM1 Files Created by EASYBOOT During System Packaging

Open it with uedit32, emedit, or any other program that can read files in hexadecimal. The first bytes are 45 42, change them to 42 4D, then change the extension to BMP and you’re done.

After modification, use PS or FW to rotate it 180 degrees, then flip it horizontally, and adjust the brightness and contrast.