How to use security dfu in app

[sun]

I used the example in nRF51_SDK_9.0.0_2e23562\examples\dfu\experimental, the first time that work well. But when I want to update a app in app(with dfu function),it failed. (When I use normal dfu ,both work well) The nRFConnect-4.3.2.apk tool show debug info: ……

[DFU] jump to bootloader send (op code = 1, uploade mode = 4) [DFU] disconnected by the remote device.

……

Why disconnected? How to resolve it

[Petter Myhre]

What do you mean by update a app in app? Could you explain a bit more about what you have done and what you want to achieve?

[sun]

That is app with dfu function (like ble_app_hrs_s110_with_dfu_pca10028 project).I know the problem maybe on my app. thanks！

[Petter Myhre]

Could you explain a bit more about what you have done and what you want to achieve? What SoftDevice are you using? You flash the SoftDevice and a bootloader, then you do DFU with which application? Then you do DFU again? With what application?

[sun]

enter code here

[sun]

I'm sorry ,my english is pool . I just want to use RF51_SDK_9.0.0_2e23562\examples\dfu\experimental and ble_app_hrs_s110_with_dfu_pca10028。 then the problem is that I used a wdt， wdt not be feeded in dfu，so 。。。