RE: How to make sure DFU erases all app data

Vidar Berg — Thu, 13 Dec 2018 12:22:22 GMT

Hi,

The bootloader will not erase the app data section unless it's required to fit the new image(s) you are uploading. If you want to guarantee that the app data reserved is erased you need to either modify the bootloader or add a mechanism in your app that erases the app data after an application update.

Maybe something like this:

1. Create a new data record that holds the current version number of the application.

2. Harcode the version number in the app or create a pointer that points to nrf_dfu_settings_t::app_version in the bootloader settings.

3. On startup, compare the version number from step 2 with the one in step 1. If there's a mismatch (ie app has been updated), erase user data then update the fds record with the new version number.