diff --git a/test/fuzz/Makefile b/test/fuzz/Makefile
index 98c17464..05a4f631 100644
--- a/test/fuzz/Makefile
+++ b/test/fuzz/Makefile
@@ -38,7 +38,7 @@ endif
 
 LDFLAGS=-lm
 # use 'make D=-DUSER_DEFINE' to pass a user define to gcc
-CFLAGS=-O0 $(D)
+CFLAGS=-O2 $(D)
 
 LWIPDIR=../../src
 CONTRIBDIR=../../contrib