off-topic apologies - how to unlock sim (not phone)

Harald Welte laforge at
Tue Feb 22 12:24:54 UTC 2011

On 02/20/2011 02:07 AM, Scott Weisman wrote:
> I apologize for this in advance. I figure the collective GSM knowledge 
> here might be able to help me.

Well, I think it is interesting from a 'scientific' point of view, i.e. 
understanding how such mechanism is implemented.

> I have a SIM card that can only be used on one phone. The phone itself 
> is unlocked. But the SIM won't work on any other phone. Does anyone 
> know anything about this or how to unlock a SIM to work on any phone?

I think the first step is to trace what is happening between phone and 
sim card, possibly by using osmocom simtrace.

Once you have a trace, you can look at the messages and try to identify 
the mechanism the SIM uses to identify the phone.  After that, you could 
possibly implement a small program for a proxy SIM like bladox or 
RebelSIM which patches the messages to make the SIM card happy.

All in all not an easy undertaking, but it can definitely be solved.


More information about the baseband-devel mailing list