I’m not sure whether the situation has improved recently, but this reminds me of Stefan Esser’s presentation about the abysmal security in iOS 6-8: https://papers.put.as/papers/ios/2015/SyScan15_Stefan_Esser_-_iOS_678_Security_-_A_Study_in_Fail.pdf The proposed solution in the article should work, though - that is, if they prevent against exploits during phone boot or DFU mode…