Patch for clock.c: JN5139 does not have "vAHI_TickTimerRegisterCallback(...)" in AppHardwareApi.h. Added define "APP_HARDWARE_API_JN5148" (in /contiki-jn51xx/cpu/jennic/jn5148/AppHardwareApi.h) to use old implementation in clock.c (from before 4a4c6587a0feb49ef7a6a74207cd4091ed0471e2) to work around this.