Introduction#

It is often required to update firmware on devices when it is not feasible to connect a J-Link debugger. In these cases, a standalone bootloader is ideal because it makes it possible to update the firmware through a Universal Asynchronous Receiver/Transmitter (UART) or Serial Peripheral Interface (SPI) connection.

In some cases, even connecting a device to a computer is problematic. In these instances, an OTA (Over the Air) bootloading process can work. This requires an application bootloader which can update the firmware from an onboard storage (like an SPI flash memory or part of the MCU flash memory). However, the OTA image transfer is still the responsibility of the main application.

For more details on bootloading basics, see UG103.06: Bootloading Fundamentals.