Originally Posted by china_user
I have an unlock code from Cingular and the Cingular rep told me to power on with the non-Cingular SIM but I don't see where I can enter the code. With this SIM (a working ChinaMobile SIM card) I get an error message under settings/options/SIM Card that reads "No valid SIM card". With the SIM card that came with the phone in the USA, the message reads "SIM Card: Security Disabled". But again, unclear to me where to enter the unlock code.
I have the same problem, but in a different context. I was planning on migrating from T-Mobile to AT&T because T-Mobile's coverage is lousy where I am in US. The 7100t I had used in UK and Viet Nam, but it refused to recognize an Orange SIM in France. AT&T said if the device is unlocked, it is unlocked, no problem put our SIM in. When I did, it said 'no valid SIM' -- everybody figured it really is still locked, and one T-Mobile person said use it again on our network after using it overseas, it gets locked again. No, I finally get to a tech person at T-Mobile who really sounds like she knows her stuff, she says once unlocked, stays that way unless you go in with a new code to lock it again. But -- although I have unlock instructions from T-Mobile -- I can't get to the SIM card to use them; the device says 'no valid SIM card' whatever I put in [if I put the old, now inactive, T-Mobile SIM in it says 'SIM card rejected.'] T-Mobile now say, probably a hardware problem -- but pretty odd that it happened when we took the T-Mobile SIM out and put the AT&T one in, don't you think? Anyone got any ideas, or do I have to buy a new BlackBerry? This device is long out of warranty.