ELECTRONIC CONTROL UNIT, RETRY POINT SPECIFYING METHOD AND COMPUTER PROGRAM PRODUCT FOR SPECIFYING RETRY POINT

An electronic control unit includes a first process flag setting unit that is configured to set a first process flag indicative of a progress of a first process that is one of a series of processes related to a program rewrite, a second process flag setting unit that is configured to set a second process flag indicative of a progress of a second process that is an other of the series of processes related to the program rewrite, and a retry point specifying unit that is configured to specify, based on the first process flag and the second process flag, a retry point for resuming the program rewrite when the program rewrite is suspended. The retry point specifying unit is further configured to store an amount of the update data that has been written until the program rewrite was suspended and request the vehicle master device to transfer the update data based on the stored amount of the update data when resuming the program rewrite.