diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index dd96d9e30..bd177108e 100644
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -459,13 +459,13 @@ GEN_PINS_QSTR = $(BUILD)/pins_qstr.h
 GEN_PINS_AF_CONST = $(HEADER_BUILD)/pins_af_const.h
 GEN_PINS_AF_PY = $(BUILD)/pins_af.py
 
-ifneq ($(FROZEN_DIR),)
+ifneq ($(FROZEN_MANIFEST)$(FROZEN_DIR),)
 # To use frozen source modules, put your .py files in a subdirectory (eg scripts/)
 # and then invoke make with FROZEN_DIR=scripts (be sure to build from scratch).
 CFLAGS += -DMICROPY_MODULE_FROZEN_STR
 endif
 
-ifneq ($(FROZEN_MPY_DIR),)
+ifneq ($(FROZEN_MANIFEST)$(FROZEN_MPY_DIR),)
 # To use frozen bytecode, put your .py files in a subdirectory (eg frozen/) and
 # then invoke make with FROZEN_MPY_DIR=frozen (be sure to build from scratch).
 CFLAGS += -DMICROPY_QSTR_EXTRA_POOL=mp_qstr_frozen_const_pool