Do post how is the firmware working for you? Keep in mind its a developer firmware that means it might have some issues. On top of it I am not sure whether it has been updated to Black yet..
the firmware is working great, and it doesn't have any issues with my phone mate, it's the same rm-821 anyway, i think all of the rm-821 independent firmware (not with AT&T, etc) wouldn't be troubled if you installed it on your phone. no probs, i updated my phone just now into windowsphone 8.1 and it's working smoothly
anyway mate, is there any way to restore backups (app, photos, text message) after i start up my phone and skip the microsoft login?
if i reset my phone AGAIN from about > reset my phone, will that downgrade my phone from windowsphone 8.1 to lumia amber again? :/
EDIT: nevermind,
reset my phone from about is NOT downgrading your firmware, only reseting your phone and erase all the data , and don't forget to restore your phone at the start up since it can't be restored later on unless you guys want restore your phone AGAIN! good day! thanks!