NRF_DFU_BLE_REQUIRES_BONDS requires NRF_SDH_SERVICE_CHANGED ?

[Allen]

Hello,

Why is SERVICE CHANGED required when using bonds? We do not require the service changed notification in our application. However I am unable to remove that feature from the Bootloader SDK configuration when requiring bonds.

Thanks

[Vidar Berg]

Hello,

The service changed characteristic is required because you need the client to start a new service discovery when it re-connects with the device in bootloader DFU mode, and similarly when it re-connects to the app after completing the DFU. The reason this isn't needed with the "unbonded" variant is that the bootloader advertises with the BLE address + 1 and thus making central see it as a different device. Relevant documentation for reference: Buttonless Secure DFU Service with bonds

Best regards,

Vidar