nrf5340 sysbuild LFCLK loop

[Domziy]

Hello, 

I have a custom nrf5340 board without a 32kHz clock attached. When using a sysbuild configuration (with MCUBOOT) and debugging the code I get stuck in this LFCLK loop:

I tried using another nrf5340dk and cut the SB1 and SB2 with the same results of the LFCLK loop. I have added the configs to both the prj.conf of the app core and net core: 

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

to the project but the results are the same. I tried changing the config to K32SRC_SYNTH and K32SRC_PPM and the problems persists. 

I am using:
-nrf5340dk_nrf5340
-SDK v2.6.0

[ecc]

I also had the same problem.  It turns out that the prj.conf settings are not applied to MCUBoot, and so I had to add

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

to sysbuild/mcuboot.conf so that MCUBoot would also be told to use the RC oscillator, instead of the XTAL.

Edit: I actually ended up putting those two lines into my custom board's defconfig file, so that the LFCLK source gets picked up no matter what type of build system is performed.