My N9 started to act strangely yesterday evening; it just never connected to either Wifi or 3G. A reboot would certainly help... or so I thought.

Right after I rebooted, I got a screen telling me (in German) than my security code has expired. I'm asked to enter the old code and then a new one (2 times). The new one must be at least 5 characters long and must consist of letters and numbers.

I did read the threads about people suddenly being asked to enter a device lock code that they never defined, and if it's really necessary I'll flash my device... (if I still can. Are the necessary files still available for download from a trustworthy source?)

But I'm not even sure what "security code" this is. The thing about both letters and numbers doesn't sound like a normal device lock at all, neither does the word "expired". (Device lock codes don't expire, do they?)

One thing I could think of is Mail for Exchange. Our company enforced provisioning quite a while after I had set up the account, and while the N9 did ask me at some time (cannot remember when) to enter a lock code, it never asked me again to enter it when I switched it on. (Is this a bug or a feature in the MfE implementation?) Because of this, I'm not 100% sure what I entered back then, but I'm pretty certain it was the PIN I also use for my SIM card... which, of course, doesn't meet the standards required now for the new code.

So before I go and wipe my device and re-flash it, I'd like to know where this "expired security code" really comes from and if I can bypass this message in a less destructive way.
(I don't know, like... like uninstall MfE altogether if it's really an MfE issue? Is this even possible?)

UPDATE: I found the mail from Oct 2013 announcing Exchange Provisioning; they said it should be a 4-digit numeric PIN. I'm pretty certain now that I used my SIM-PIN. That makes it less likely I'm dealing with an Exchange problem here. So where does the "more than 5 characters alphanumeric security code" come from???

Device lock expires on my N9 as well (Settings-> Security-> Device Lock) periodically (might be done by MfE). My company also enforced provisioning. Initially itself I set the lock code as a combination of digits and letters.

Yes its comes from MfE provisioning, there is a way to apply hack with aegis exploits to make provisioning void and even disable device lock while using mfe, but most likely that hack would be against your company policy.

New information: The IT people in my company told me that our Exchange server does not require the security PIN to be changed. It never expires.

Also, Exchange would still ask for a 4-digit numeric PIN; the "5-characters, numbers and letters"-thing certainly does not come from the Exchange server.

Sooooooo.... what strange thing is known for "security codes" that must be at least 5 characters, with letters and numbers mixed?

So basically it must be a bug in the MfE implementation if

• the server did not ask for a new code
• the restriction given don't correspond to the restrictions given by our exchange server (alphanumeric vs. numeric, 5 vs 4 chars)
• the existing code (which corresponds to my SIM-PIN) is not recognised?

I wouldnt want to hack it so that there's no PIN at all anymore. I just want my existing PIN to be recognized.