Looks like I'm joining you on this one... My LG Optimus 7 decided to reset itself recently (after the Mango update), to the dreaded 'emergency call' screen. This has happened with every WP7 I have owned (HTC Trophy & HTC HD7). However, both the HTC phones were completely reset when the bug hit me.
The LG seemed (at first), to handle the glitch better than the HTC's, as after the reset, all my apps/contacts/pictures etc were still on the phone. However, it looks like she has lost the ability to hang onto a data connection.
Calls are fine, but some txt messages fail to arrive (despite the delivery report on the other end). My carrier assure me that there is no congestion on my number. The mobile data connection has disappeared completely. I have no 3G or even Edge connection and I can only use WiFi to connect to the internet. Network Setup shows 'setting files are being updated and your handset will be rebooted', with a single 'OK' option. I have tried pressing OK and leaving the phone overnight, not pressing OK and leaving the phone overnight and both the the above followed by a power off/on cycle in the morning.
I have tried a hard reset (within the phone) and a cold boot (Vol +- & Camera & power). None of which have brought back my data connection (but they both did a cracking job of wiping my phone of all data, which is annoying, seeing as Microsoft don't deem a full backup as necessary)!
Just thought I'd throw in my bit. I'm in the Isle of Man using Sure (cable & wireless) - however, I may as well be living on the moon using a potato.
Disappointed.