Well, we have NFC why those are crashing, if it is a SIGILL crash, then thumb errata workaround is not working and we will have to pray Nokia for a new Secure Monitor, which sets ACTLR.IBE bit . On the other hand it is better to gather some logs first, analyze them and make conclusions. EDIT: If i have time tomorrow I will enable the errata in KP and will modify it to dump the contents of ACTLR, so I will be able to check if we have access to that bit from non-secure mode. If we can't change it, the thumb errata does nothig and we will have to pester and pray for a new Secure Monitor. If the bit can be changed, then arm thumb errata works as it should, but we have another problem yet to be investigated. @ivyking - any chance to gather some logs and/or coredump?