Method and apparatus for secure multi-cycle vehicle software updates

A system comprising:

• a vehicle module including at least an updateable memory and storing a verification counter value usable for authentication of memory-state change commands based on an authentication counter value received from outside the module;
• a vehicle-processor configured to:
• send an authentication request, including the authentication counter value, to a module for a module memory-state change command;
• send a memory-state change command responsive to receiving authentication, based on the sent authentication counter value, from the module;
• repeat sending the authentication request and memory-state change command over multiple vehicle key cycles until the module completes the memory-state change command;
• responsive to completion of the memory-state change command, receiving an updated verification counter value from the module;
• and
• updating the authentication counter value to match the updated verification counter value.