diff --git a/bricks/stm32/stm32.mk b/bricks/stm32/stm32.mk
index 1ffab67a1..bb9c6ea88 100644
--- a/bricks/stm32/stm32.mk
+++ b/bricks/stm32/stm32.mk
@@ -406,7 +406,7 @@ LWRB_SRC_C = lib/lwrb/src/lwrb/lwrb.c
 
 # libfixmath
 
-COPT += -DFIXMATH_NO_CTYPE -DFIXMATH_NO_CACHE
+COPT += -DFIXMATH_NO_CTYPE -DFIXMATH_NO_CACHE -DFIXMATH_FAST_SIN
 
 LIBFIXMATH_SRC_C = $(addprefix lib/libfixmath/libfixmath/,\
 	fix16_sqrt.c \