简单谈谈自己回国使用的情况，希望某些信息能对大家有用。
临走前让verizon给解了锁，被告知下面的说法
SIM unlock requirements for Iphone 4s
Once the 3rd party prepaid or overseas carrier SIM is inserted, device
will "brick" and will require unbricking. Start unbricking process via
local Wi-Fi or iTunes tether at international destination. Once process has
started device will perform a system check (data push-pull) with new SIM
inserted to validate SIM Unlock. You will need to perform the same steps
with the Verizon Wireless sim card in the device after returning to the USA.
听着"brick"怪吓人而且挺麻烦，但也只好这样了。结果拿回国后到联通买了sim卡后，
工作人员用专门的工具给剪成小卡，塞进iphone 4s里直接就认出了联通，不用上面提
到的一堆手续，也没有reboot。回美后开机后不认verizon的服务（因为还是联通的sim
卡），换回verizon原来自带的卡后马上就认，不清楚这到底是为啥？有懂的人给扫扫
盲吧
