Posted by:
icedtea
(
)
Date: October 20, 2014 09:05PM
Unlocking is pretty simple: Google is your best friend here. You can buy codes online or get a local unlock service.
If you're trying to install 8.1 on a locked phone with no service, you might well see spinning gears. Lots of users are having the same error when trying to install the newest update even on the 920 and other models. Here's a link on resetting and wiping (albeit one to T-Mobile) that might help:
http://support.t-mobile.com/docs/DOC-6809You'll still have to get it unlocked to use it, though. Since the 520 and 521 are bottom-of-the-line Windows phones and are pretty cheap, you might weigh the cost of getting it unlocked vs. just buying one that works with your new carrier.
Good luck!