Will data stored with FDS survive a firmware upgrade?

[Paul Dunn]

I'm running an nrf52832, using SDK 11.0 and the S332 soft device. I've had instances where it seemed my flash data, stored with FDS, was corrupt after a firmware upgrade. Note that generally this is not the case, but infrequently I have had issues.

I've not investigated the root cause yet. I'd like to confirm that the expectation is that FDS data is safe from a firmware upgrade. I.E. all FDS metadata is stored somewhere where it is not changed by a FW update. Note that I am in the process of upgrading to SDK V12.2.0, so please be clear if this answer depends on the SDK version.

I could not find any indication about persistence of data after FW update in the FDS documentation.

Thanks....

[Hung Bui]

Hi Paul,

Have you declare the size of your application data that the bootloader shouldn't touch ? It's described here.

In addition, how is your fds configuration in the new firmware compare to the old firmware ? Do they have the same size ? It could be an issue if you reduce the size of fds in your new firmware, as it would cause data corruption. If it's the case, you need to wipe out the data and re-initialize it.

[Paul Dunn]

Thanks for the tip on DFU_APP_DATA_RESERVED. I had not set that. (Well, actually I had it set to zero.) I'll implement that properly and re-test.