With the rapid development of intelligent connected vehicles and the gradual popularization of intelligent driving technologies, the number of on-board electronic control unit ECU modules has significantly increased, and the software functions have become increasingly complex. It is particularly important to implement a reliable and secure online upgrade OTA mechanism. This article proposes a technical implementation scheme based on software for AB partition switch (AB Swap), which can achieve a dual-system partition backup and switching mechanism without increasing additional hardware costs, effectively ensuring system stability and fault-tolerant capability during the OTA process. This scheme is implemented based on the existing module's hardware solution and provides a new idea for improving the scalability and platform applicability of the existing solution.