UnsignedFlash

That's pretty cool! I wonder how properly they were really signed - there are _so many_ mistakes even in systems that at least don't use an example key off the Internet. The most common ones I know of are: * Out-of-bounds write issues allowing "signature was validated" flags to be overwritten in Flash memory, like https://github.com/jglim/UnsignedFlash * State machine mistakes, like https://github.com/bri3d/VW_Flash/blob/master/docs/docs.md - allowing Flash to be written again after it was already written, without an erase first. * File format parsing mistakes, like those in a number of VW AG head units: https://github.com/jilleb/mib2-toolbox/issues/122 * The use of RSA with E=3 and inadequate padding validation, like https://words.filippo.io/bleichenbacher-06-signature-forgery... . * Failure to understand the system boundaries, like in t

The XOR encryption was just for the update container. Newer update files usually employ some stronger forms of compression/encryption. However, it's usually some strange in-house crypto, so eventually people figure it out. bri3d refers to using RSA signatures on the firmware once it's written to the flash. By ensuring the firmware is signed using the manufacturers private key it should (in theory) prevent messing with the firmware, even if all encryption/flashing steps have been reverse engineered. Some interesting reading: https://github.com/bri3d/VW_Flash/blob/master/docs/docs.md https://github.com/jglim/UnsignedFlash