I'm using nRF5 SDK V12.2 to do the OTA for nRF52832 . In general, it's ok. However, if I close the bluetooth function on the phone or close the DFU app from the nRF toolbox to make some bad condition, the OTA is interrupted and it will stay at bootloader all the time and never switch to the original application. For the nRF5 SDK V11.0, the bootloader will switch to the original application when OTA fails. So could you tell me how to make it witch to the original application when OTA fails? Thanks.
you are correct that the Secure Bootloader in SDK v12.x.x will not timeout if there is no DFU activity and jump to the original application.
You can implement a timeout using the WDT, see this answer, or you can use the RTC, see this answer. I recommend using the WDT approach as this is the easiest to implement.
Do you mean that after you flash the BL+Settings+Application+ SoftDevice the nRF52 jumps to the application? Or do you mean that you cannot etter the bootloader from the application? If its the latter , how are you triggering the switch from application to bootloader? Is it by holding down a button or have you implemented buttonless DFU?
Are you using the WDT in your application?
It's OK now. There is something wrong with my PC