diff --git a/py/mkrules.cmake b/py/mkrules.cmake
index b29986585a..38bad80fdb 100644
--- a/py/mkrules.cmake
+++ b/py/mkrules.cmake
@@ -205,7 +205,7 @@ if(MICROPY_FROZEN_MANIFEST)
 
     add_custom_command(
         OUTPUT ${MICROPY_FROZEN_CONTENT}
-        COMMAND ${Python3_EXECUTABLE} ${MICROPY_DIR}/tools/makemanifest.py -o ${MICROPY_FROZEN_CONTENT} -v "MPY_DIR=${MICROPY_DIR}" -v "MPY_LIB_DIR=${MICROPY_LIB_DIR}" -v "PORT_DIR=${MICROPY_PORT_DIR}" -v "BOARD_DIR=${MICROPY_BOARD_DIR}" -b "${CMAKE_BINARY_DIR}" -f${MICROPY_CROSS_FLAGS} ${MICROPY_FROZEN_MANIFEST}
+        COMMAND ${Python3_EXECUTABLE} ${MICROPY_DIR}/tools/makemanifest.py -o ${MICROPY_FROZEN_CONTENT} -v "MPY_DIR=${MICROPY_DIR}" -v "MPY_LIB_DIR=${MICROPY_LIB_DIR}" -v "PORT_DIR=${MICROPY_PORT_DIR}" -v "BOARD_DIR=${MICROPY_BOARD_DIR}" -b "${CMAKE_BINARY_DIR}" -f${MICROPY_CROSS_FLAGS} --mpy-tool-flags=${MICROPY_MPY_TOOL_FLAGS} ${MICROPY_FROZEN_MANIFEST}
         DEPENDS MICROPY_FORCE_BUILD
             ${MICROPY_QSTRDEFS_GENERATED}
             ${MICROPY_ROOT_POINTERS}