diff --git a/STM32F1/platform.txt b/STM32F1/platform.txt
index a58d569bd..0f51c6c94 100644
--- a/STM32F1/platform.txt
+++ b/STM32F1/platform.txt
@@ -36,7 +36,7 @@ compiler.define=-DARDUINO=
 # this can be overriden in boards.txt
 build.f_cpu=72000000L
 build.mcu=cortex-m3
-build.common_flags=-mthumb  -march=armv7-m -D__STM32F1__ -DARDUINO_ARCH_STM32
+build.common_flags=-mthumb  -march=armv7-m -D__STM32F1__
 build.variant_system_lib=libmaple.a
 ## LED stuff is not really used but is still required in the code
 build.error_led_port=GPIOB