DFU Compatibility

[Aymen Rejeb]

Hello Nordic Team,

I would like to know if it is possible to do a DFU of my SDK10 based application (s130_nrf51_1.0.0_softdevice + SDK10 Bootloader) on an nRF51822 (32 KB RAM/ 256 KB FLASH) by an SDK12.2.0 based application (bootloader_secure + s130_nrf51_2.0.1_softdevice) ?

Is there an compatible combination to do that?

Many thanks in advance.

[bjorn-spockeli]

Hi Ayman,

the Secure bootloader in SDK v12.0.0 and later allows you to sign the firmware images. However, this bootloader is considerably larger(~24kB) compared to the Legacy bootloader(~15kB) in SDK v11.0.0 or older, which means that it is not possible to update from the legacy to the secure bootloader unless the size bootloader region was initially set to 24kB. The new bootloader image must have the same start address as the old image, i.e. the new image cannot be larger than the old bootloader and if its smaller it must still have the same start address. This is because the bootloader start address is written to the UICR registers of the nRF51, which cannot be altered without erasing the entire chip and then re-flashing the chip with a programmer.

Best regards

Bjørn

[Aymen Rejeb]

Hi Bjørn,

Thank you for the swift and clear response.

Best Regards,

Ayman.