I have tried and failed at making a custom IPSW. I extracted the DMG, decrypted it, decompressed it, modded it, recompressed it, and packaged it as an ipsw. I tried restoring to it, and now I am in recovery mode. Is there any failsafe method of modifying and IPSW --- and I don't mean jailbreaking the root fs. I just want to modify some plists.