Description: BLE Multistep-OAD (MS-OAD), also known as Optimized OAD, is a new firmware upgrade method that optimizes flash memory allocation during Over-The-Air Download (OAD) operations by splitting firmware into two halves. This approach frees up substantial flash space for application development while maintaining secure and reliable firmware updates. It also provides users with increased development space for their applications and supports rollback scenarios for version swap protection.