STM32 Custom Bootloader (Part 4): Implement OTA FLAG Mechanism

Build an *STM32 OTA request mechanism* that allows the application to tell the bootloader when a firmware update is required, using a Flash-based OTA flag. In this tutorial, we continue the STM32 custom bootloader series and implement an *OTA FLAG mechanism* using the application header. The application sets the OTA flag in Flash and resets the MCU, allowing the bootloader to detect the request after reset and decide whether to start the OTA process or continue with normal application validation. The bootloader reads the OTA flag, clears it after detection to prevent repeated OTA requests, and then enters the OTA update flow. Since the actual firmware flashing is implemented in the next part, we use an external button to simulate the OTA request and a blinking LED to represent the OTA flashing state. #STM32 #STM32Bootloader #EmbeddedSystems #Bootloader 📁 *Download Project Files & Full Article:* https://controllerstech.com/stm32-ota-bootloader-flag-mechanism/ 📁 *STM32 Tutorials:* https://controllerstech.com/stm32-tutorials/ 📁 *ControllersTech Home:* https://controllerstech.com/ ### ▶︎ Related Videos 1️⃣ *CRC Based Application Validation:* https://youtu.be/8-HSYugyeA8 2️⃣ *Complete STM32 OTA Firmware Update:* https://youtu.be/iwxWuUbizVA