diff --git a/firmware/Makefile b/firmware/Makefile
index d122096cc2..b87fa5c3eb 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -186,8 +186,14 @@ include $(CHIBIOS)/os/hal/osal/rt-nil/osal.mk
 include $(CHIBIOS)/os/rt/rt.mk
 include $(CHIBIOS)/os/common/ports/ARMCMx/compilers/GCC/mk/port_v7m.mk
 # EX files (optional).
-include $(CHIBIOS)/os/ex/devices/ST/lis2dw12.mk
-include $(CHIBIOS)/os/ex/devices/ST/lsm303agr.mk
+ifeq ($(EFI_ONBOARD_MEMS_LIS2DW12),yes)
+  DDEFS += -DEFI_ONBOARD_MEMS_LIS2DW12=TRUE
+  include $(CHIBIOS)/os/ex/devices/ST/lis2dw12.mk
+endif
+ifeq ($(EFI_ONBOARD_MEMS_LIS2DH12),yes)
+  DDEFS += -DEFI_ONBOARD_MEMS_LIS2DH12=TRUE
+  include $(CHIBIOS)/os/ex/devices/ST/lsm303agr.mk
+endif
 include $(CHIBIOS)/os/hal/lib/streams/streams.mk
 include $(CHIBIOS)/os/various/cpp_wrappers/chcpp.mk
 
diff --git a/firmware/config/boards/hellen/hellen-honda-k/board.mk b/firmware/config/boards/hellen/hellen-honda-k/board.mk
index d10b018254..115e13fa38 100644
--- a/firmware/config/boards/hellen/hellen-honda-k/board.mk
+++ b/firmware/config/boards/hellen/hellen-honda-k/board.mk
@@ -28,11 +28,11 @@ DDEFS += -DMMC_USE_MUTUAL_EXCLUSION=TRUE
 DDEFS += -DEFI_ONBOARD_MEMS=TRUE
 
 # May be it is LIS2DW12?
-# DDEFS += -DEFI_ONBOARD_MEMS_LIS2DW12=TRUE
+# EFI_ONBOARD_MEMS_LIS2DW12 = yes
 # DDEFS += -DLIS2DW12_USE_SPI=TRUE -DLIS2DW12_SHARED_SPI=TRUE
 
 # But on my board this is LIS2DH12 that is compatible with LSM303AGR
-DDEFS += -DEFI_ONBOARD_MEMS_LIS2DH12=TRUE
+EFI_ONBOARD_MEMS_LIS2DH12 = yes
 DDEFS += -DLSM303AGR_USE_SPI=TRUE -DLSM303AGR_USE_I2C=FALSE -DLSM303AGR_SHARED_SPI=TRUE
 
 include $(BOARDS_DIR)/hellen/hellen-common144.mk