Just change the file extension, the only difference between .bin and .rom for bios files is literally just the extension.
I've still got the cards, and I think I still have a backup of the original BIOS saved somewhere, although it will only work for this precise card, (KFA2/Galaxy 550TI White Edition) as it's a custom PCB and parts job. Gimme a few minutes to fish it out, although I'm really not responsible if your card does stop working because you're trying to flash an OC bios from another card onto yours. Edit; Okay. This is the BIOS dump straight off my first card. https://drive.google.com/file/d/0B0H3PcHsJy_vbEpDS2FVVnM4UVE/edit?usp=sharing I can't remember if I've fiddled with it or not, but it should still flash okay to any other White Edition.