Can DFU BLE service be used for data (not application) update?

[yes]

Our products are based on nRF52832 & nRF52840 and include display.

We use DFU mechanism for application update.

According to Nordic's documentation DFU supports multi-application i.e. more than one application on flash memory.

Can we use the DFU service for updating separated data (non-application) sectors e.g. change languages files without updating application?

Thanks in advance 

[Andy]

You can, but it will naturally not work out of the box, i.e. you will need to modify the bootloader.

I have used the DFU service to update a STM32 microprocessor through the NRF52. This allowed my device to support STM firmware updates over BLE.

You can do whatever you want with the data you receive through the DFU service, you just need to figure out a mechanism to distinguish when data is meant to be used for an application update and when data is meant to be used for language file updates.

[yes]

Correct if I am wrong, the difference shall be if in the end of the process the MBR shall be updated and the system shall be reboot?

The data (language -  strings) is used by the application but we want to separate between the data and the application   and have the option to update one of them without changing the other.

[Andy]

I’m not sure what you mean with “language - strings”, but the point is that you can use the data provided on the DFU service as you please. The bootloader as shipped with the SDK takes whatever you send to it and puts it where the application is supposed to be.

You can modify the bootloader to put the data elsewhere. You just need to differentiate when the data is supposed to be treated as an application update and when it’s supposed to be treated as a data update.