This application relates to the field of intelligent connected vehicles, and provides a variable-rate OTA
upgrade method, device, and VBOX. The method includes: sending a first
message frame to a target ECU at a first master
control bus rate; determining a second slave
control bus rate and a second master
control bus code based on a first slave control load rate and a first slave control
bus rate extracted from a first response message; sending the second slave control
bus code to the target ECU to cause the target ECU to adjust the first slave control
bus rate to a second slave control bus rate corresponding to the second slave control bus code; adjusting the first master control bus rate to a second master control bus rate consistent with the second slave control bus rate; and sending a second
message frame to the target ECU at the second master control bus rate. This application can achieve variable-rate
data transmission and
upgrade flashing based on the ECU's flashing capability and load rate, thereby achieving optimal
upgrade flashing with high efficiency.