I've spent the better part of today trying to unlock my iphone all to no avail...
Located in China and read a thread on updating Cydia in China, and followed all the steps as best as I could, but still not working.

Here are the steps I followed:
1. Jailbreak using Spirit
2. Download iphone browser
3. Downloaded afc2add on Cydia
4. Edited hosts file located under CWindows\System32\drivers\etc to
# Host Database
# localhost is used to configure the loopback interface
# when the system is booting. Do not change this entry.
## localhost broadcasthost
::1 localhost
fe80::1%lo0 localhost
echo " cache.saurik.com

5. Replaced hosts file in iphone root directory using iphone browser

Reopened Cydia and tried to update and install Ultrasn0w, but still not working.