nrf: Only search for frozen files if FROZEN_MPY_DIR is set
@@ -206,8 +206,10 @@ SRC_C += \
device/$(MCU_VARIANT)/system_$(MCU_SUB_VARIANT).c \
device/$(MCU_VARIANT)/startup_$(MCU_SUB_VARIANT).c \
+ifneq ($(FROZEN_MPY_DIR),)
FROZEN_MPY_PY_FILES := $(shell find -L $(FROZEN_MPY_DIR) -type f -name '*.py')
FROZEN_MPY_MPY_FILES := $(addprefix $(BUILD)/,$(FROZEN_MPY_PY_FILES:.py=.mpy))
+endif
OBJ += $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
OBJ += $(addprefix $(BUILD)/, $(SRC_LIB:.c=.o))
