diff --git a/keyboard/stm32_onekey/Makefile b/keyboard/stm32_onekey/Makefile
index d84bfa4b..3868ee3d 100644
--- a/keyboard/stm32_onekey/Makefile
+++ b/keyboard/stm32_onekey/Makefile
@@ -35,6 +35,9 @@ MCU_STARTUP = stm32f0xx
 # it should exist either in <chibios>/os/hal/boards/
 #  or <this_dir>/boards
 BOARD = ST_STM32F072B_DISCOVERY
+# Cortex version
+# Teensy LC is cortex-m0; Teensy 3.x are cortex-m4
+MCU  = cortex-m0
 # ARM version, CORTEX-M0/M1 are 6, CORTEX-M3/M4/M7 are 7
 ARMV = 6
 # If you want to be able to jump to bootloader from firmware on STM32 MCUs,
diff --git a/tmk_core/tool/chibios/chibios.mk b/tmk_core/tool/chibios/chibios.mk
index d1738c13..0f6af53d 100644
--- a/tmk_core/tool/chibios/chibios.mk
+++ b/tmk_core/tool/chibios/chibios.mk
@@ -162,8 +162,6 @@ INCDIR = $(STARTUPINC) $(KERNINC) $(PORTINC) $(OSALINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m0
-
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
 CC   = $(TRGT)gcc