Disclosed embodiments relate to opportunistically updating Electronic Control Unit (ECU) software in a vehicle. Operations may include receiving, at a controller in a vehicle, a wireless transmission indicating a need to update software running on at least one ECU in the vehicle; monitoring an operational status of the vehicle to determine whether the vehicle is in a first mode of operation in which an ECU software update is prohibited; delaying the ECU software update when the operational status is prohibited; continuing to monitor the operational status of the vehicle to determine whether the vehicle is in a second mode of operation in which the ECU software update is permitted; and enabling updating of the at least one ECU with the delayed ECU software update when it is determined that the vehicle is in the second mode of operations.