diff --git a/src/makefile b/src/makefile
index 792991f..5f85ae9 100644
--- a/src/makefile
+++ b/src/makefile
@@ -5,7 +5,7 @@
 CFLAGS := -mmcu=atmega32u4   	# processor type (teensy 2.0); must match real life
 CFLAGS += -DF_CPU=16000000   	# processor frequency; must match initialization in source
 CFLAGS += -std=gnu99         	# use C99 plus GCC extensions
-CFLAGS += -Os                	# optimize for size
+CFLAGS += -Os  -flto         	# optimize for size
 CFLAGS += -Wall -Werror      	# enable lots of common warnings
 CFLAGS += -fpack-struct      	# pack all structure members together without holes
 CFLAGS += -fshort-enums      	# allocate compact enums