BLE connection persistence during FOTA update

[Ville Olo Health]

Hi!

I'm able to update the firmware on the nrf5340 over BLE but the BLE settings seem to get overwritten during the update. The master device cannot automatically reconnect to the nrf5340 and needs to be manually reconnected. Is there a way to keep the old connection during the update?

-Ville

[Hung Bui]

Hi Ville, 

The original connection has to be terminate when doing DFU update that's unavoidable. It's because the chip has to be reset for the application to be replaced. 

The question here is should the central device re-connect automatically. On normal working condition, if the device turn off and then turn back on, would the central reconnect automatically ? 
Do you see any address change when the device get updated ? Do you do pairing/bonding between the two devices ? Do you need to re-bond after DFU update ?

[Ville Olo Health]

Ah, my question was worded a bit wrong. The connection is ok to sever but the device is unable to rebond with the new software even though the address stays the same. Is there a way to keep the bond information during the update? The problem might be on the central side.

[Hung Bui]

Hi Ville, 
Did you use nRF Connect app to do DFU update or you used Device Manager. 
There is an option to delete or not delete application data when doing DFU. 
On nRF Connect app the default is to erase application data. You can change that by go to Settings -> Mcu Manager Options -> Erase application settings 

On Device Manager , if you don't click on Factory reset it will not delete bond information. 

[Ville Olo Health]

Well I'll be! I don't know how I have missed that setting. Thank you!