Bootloader hangs until I connect with J-Link RTT viewer

[Alex B]

I set the NRF_LOG_BACKEND_RTT_ENABLED 1 and NRF_LOG_ENABLED 1 in the bootloader and application. After a reset, the application gets stuck in the bootloader Or maybe (bl starts the app and reboots immediatly back to the bootloader in a loop).

When I open the J-Link RTT viewer, the log is flushed and the appilication starts running fine. I can then reset the device and it goes from bootloader to application without problem.

If I disconnect the j-link or/and exit or/and remove the probe the code continues to run until I reset the device where it get stuck again.

The problem is intermittent, when I start the debugger on the bootloader code and stop it. The code starts running fine again even after reset without RTT viewer connected.

I am puzzled. Any ideas why the RTT would block execution. Thanks,

[bjorn-spockeli]

Hi Alex, it could be that you're filling up a buffer which causes the execution to halt until its empty if Logging is enabled and you do not have a J-Link debugger connected.