diff --git a/unix/Makefile b/unix/Makefile
index 655f26bb93..ed6ae45775 100644
--- a/unix/Makefile
+++ b/unix/Makefile
@@ -176,6 +176,34 @@ SRC_QSTR += $(SRC_C) $(LIB_SRC_C)
 # SRC_QSTR
 SRC_QSTR_AUTO_DEPS +=
 
+ifneq ($(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).
+MPY_CROSS = ../mpy-cross/mpy-cross
+MPY_TOOL = ../tools/mpy-tool.py
+FROZEN_MPY_PY_FILES := $(wildcard $(FROZEN_MPY_DIR)/*.py)
+FROZEN_MPY_MPY_FILES := $(addprefix $(BUILD)/,$(FROZEN_MPY_PY_FILES:.py=.mpy))
+CFLAGS += -DMICROPY_QSTR_EXTRA_POOL=mp_qstr_frozen_const_pool
+CFLAGS += -DMICROPY_MODULE_FROZEN_MPY
+CFLAGS += -DMICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE=0 # not supported
+CFLAGS += -DMPZ_DIG_SIZE=16 # force 16 bits to work on both 32 and 64 bit archs
+OBJ += $(BUILD)/$(BUILD)/frozen_mpy.o
+
+# to create output directory for .mpy files
+$(BUILD)/$(FROZEN_MPY_DIR):
+	$(MKDIR) -p $@
+
+# to build .mpy files from .py files
+$(BUILD)/$(FROZEN_MPY_DIR)/%.mpy: $(FROZEN_MPY_DIR)/%.py | $(BUILD)/$(FROZEN_MPY_DIR)
+	@$(ECHO) "MPY $<"
+	$(Q)$(MPY_CROSS) -o $@ $^
+
+# to build frozen_mpy.c from all .mpy files
+$(BUILD)/frozen_mpy.c: $(FROZEN_MPY_MPY_FILES) $(BUILD)/genhdr/qstrdefs.generated.h
+	@$(ECHO) "Creating $@"
+	$(Q)$(PYTHON) $(MPY_TOOL) -f -q $(BUILD)/genhdr/qstrdefs.preprocessed.h $(FROZEN_MPY_MPY_FILES) > $@
+endif
+
 
 include ../py/mkrules.mk
 
diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h
index d9cfbc9190..463f5fe8cf 100644
--- a/unix/mpconfigport.h
+++ b/unix/mpconfigport.h
@@ -64,7 +64,9 @@
 #define MICROPY_LONGINT_IMPL        (MICROPY_LONGINT_IMPL_MPZ)
 #define MICROPY_STREAMS_NON_BLOCK   (1)
 #define MICROPY_OPT_COMPUTED_GOTO   (1)
+#ifndef MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
 #define MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE (1)
+#endif
 #define MICROPY_CAN_OVERRIDE_BUILTINS (1)
 #define MICROPY_PY_FUNCTION_ATTRS   (1)
 #define MICROPY_PY_DESCRIPTORS      (1)