When developing DFU OTA function APP, it can't come out in bootloader mode

[ArchieL]

Now I am using Nrf52832,SDK15.0.0, S132,

When we developed the DFU OTA function APP, we encountered some abnormal situations: it could not get out in the bootloader mode, and it also became bricked. Use single bank mode, safe DFU.
Now I am going to update the SDK version to 15.0.3 or higher, because the verification link is added for the higher version of the DFU SDK.
Are there any other reasons? How to verify and solve it?
Thank you

[Vidar Berg]

Hello,

When you say bricked, does it mean that the only way to recovert the device is to re-program it with an external programmer? Also, does the new application run ok if you program it directly with the programmer?

Best regards,

Vidar