[Q]XT910 umts - Get back to GB ? topic

Hello,

I've get a old razr and want to sell it. But i need to get back to GingerBread before.
I don't know if it's possible.
My Razr is under CM12.1 with the last safestrap and Fasboot v0A.77.

Another question, where can i find the sbf files for GB ? All links are dead.

Thanks for answer.