Device stuck after NVIC_SystemReset() or sd_nvic__SystemReset()

[Matze]

Hello,

I'm using a nRF51422 uController (Custom board) with the Softdevice s130 withe SDK 11. I want to go back into the bootloader from my application after I told the application that a new update is avalible. I set NRF_POWER->GPREGRET to 0xB1 so it would start the DFU and used NVIC_SystemReset() afterwards to reset the device. I already tired to use sd_nvic_SystemReset() aswell but the same error happens. I set a LED to light up when the device goes into bootloader mode but it's just black.

Why am I stuck? How can I reset my device as wanted?

[Matze]

UPDATE:

The problem was that I used NRF_POWER->GPREGRET in the application but I needed to use sd_power_gpregret_set(0, 0xB1) to set the Bits. Now the bootloader is started (I can tell because of the LED) but it exist the bootloader direktly. I don't understand why it wouldn't wait for the DFU as usual.

What is the problem?

[Vidar Berg]

The application has limited access to the POWER peripheral when the softdevice is enabled. I.e., can only be accessed through SD API. So your program probably didn't reach sd_nvic_SystemReset().

Try to comment out the init_softdevice check in ble_stack_init in the bootloader. Softdevice needs to be invoked again if you do a system reset from the application. The Buttonless DFU example does not do full system reset to "jump" to the bootloader, but branches to its reset handler instead.