Well I can't understand why this issue is such a blocker for N9 users. It happened to me once on my N950, but on N9 you can easily get your security code back, by using Nemesis Service Suite. (Section 308 Key 5) It somehow doesn't work for N950, but I can confirm it myself it works on N9.

Then you can set your device "non provisionable" on MfE and disable devicelock timeout.