SDK 13.0: fds_init() causes errors unless doing a full FLASH erase

[ivan]

We are evaluating the nRF5 SDK 13.0 to upgrade our projects from v12.0 and it looks like it has a bug related to the FDS functionality.

I managed to reproduce it on the clean ble_app_hids_mouse example. Simply building and programming it together with the softdevice on a device that previously ran code from SDK v12 results in the following behavior:

1. peer_manager_init() eventually calls fds_init() with the following call stack:

   pages_init()
   fds_init()
   pds_init()
   pm_init()
   peer_manager_init()
   main()
   

2. pages_init() searches the FLASH pages for pages with its signature, does not find enough and returns with the NO_SWAP error.

3. As a result, pm_init() fails and the firmware hangs in app_error_handler().

Doing a full FLASH erase before programming the firmware seems to help. Is there a better workaround to this?

[ivan]

pages_init() returns NO_SWAP. Then fds_init() quits with FDS_ERR_NO_PAGES. I did not change any settings, just downloaded a clean SDK v13, built the project with gcc/make and programmed it. The same device was previously used to try out several different projects, so the FLASH memory contents could contain random bits of other firmware.