I disabled my SIMs to be sure to not cause roaming costs; when buying a local SIM card, the seller simply removed the battery (with both SIMs disabled). This however rendered my SIMs unuseable: when I (re-)start the phone it tells me that the SIMs are locked and cannot be used. If I have a working SIM inside (the new, local one) I also cannot bypass the screen (although in the background I see that messages are arriving, etc).
I inserted the SIMs in another phone and could activate them without problems. However, Android seems to remember that the SIMs are disabled and does not allow me to unlock them by entering the PIN.
This might be a Android-Generic problem, however, I did not find any general solution for this problem. So this is my last chance before having to do a factory reset. Hence: hope you have an idea