diff --git a/board/build.mk b/board/build.mk
index 9f2c4250c2c772..926a9a34c80aac 100644
--- a/board/build.mk
+++ b/board/build.mk
@@ -1,4 +1,4 @@
-CFLAGS += -I inc -I ../ -nostdlib -fno-builtin -std=gnu11 -Os
+CFLAGS += -I inc -I ../ -nostdlib -fno-builtin -std=gnu11 -O2
 
 CFLAGS += -Tstm32_flash.ld