How to merge DFU application into ble_app_uart ?

[John12]

Hi, I'm developing an application based on ble_app_uart, and integrate FOTA is the last feature.
I'm using sdk16, S140, nRF52833. I plan update firmware over BLE, so I have followed some guide such as thread, thread
I try to run example secure_bootloader s140_debug and it work on my custom board

But now I don't know where I start. I have experience merge saadc, pwm, libuarte into ble_app_uart, so adding libraries is not my problem. DFU is quite complicated
1. I need to change some config like bootloader's flash address, flash_placement.xml, sdk config, linker or somethings....?
2. I have 2 option DFU =>  buttonless or button which example should I follow to reference
3. What is important step may I miss ?

So, first please give me some link, advise to start with DFU integrated into ble_app_uart ? Where I should start ? what are configurations ?
Thank u so much
Best regard !

[mtsunstrum]

The DFU/FOTA ( secure bootloader ) does not get merged into your application.

It stands alone, and is executed upon bootup. Once it has finished, it will transfer control to your application.

Yes, there are settings like flash_placement.xml, etc ... which will set aside flash space for the FOTA ( secure bootloader ). You will also need to generate a settings.hex file.

The general process is a tiny bit complicated, but once steps are followed, it works well.