Just a short update. I've bought nrf52dk and build lora_app_shell for this target - still crashes. Tried loraping app - crashes on both nrf devkits. Slinky works fine on both, tried btshell app on nrf52dk - it works. Updated SX1276 SPI pins according to bsp.c and updated syscfg with SX1276_SPI_CS_PIN and other mentioned earlier defines - lora app still crashes.
Hope I'll have enough free time on weekend to debug deeper. I appreciate your help!
