Abstract: To achieve reliable program upgrades for the suspension, guidance, and braking controller boards of normal-conducting high-speed maglev trains, a bootloader program and an application program were designed. This solution involves adding a download request reception function in the application program, followed by writing a program upgrade flag into the flash memory. Upon the next power-up, the bootloader reads the data at a fixed address. If the flag indicates a program upgrade, the system enters the upgrade mode. Through communication between the bootloader and the host computer, the application program is written to a fixed address in the flash memory. The communication protocol incorporates handshake mechanisms, error retransmission mechanisms, and verification mechanisms. Otherwise, the system proceeds to the application program. This scheme replaces the traditional method of updating the flash memory"s application program via the JTAG emulation interface, significantly simplifying the maintenance and upgrading of embedded application software. The proposed CAN bus-based application program update method greatly reduces labor and material costs when upgrading programs on numerous suspension, guidance, and braking controller boards, thereby lowering the upgrade and maintenance costs for embedded terminal device programs.