diff --git a/make/mips_app.mk b/make/mips_app.mk
index b03fa43..af0b543 100644
--- a/make/mips_app.mk
+++ b/make/mips_app.mk
@@ -1,5 +1,5 @@
 CFLAGS-sim := -Os
-CFLAGS-ml402 := -g -O2
+CFLAGS-ml402 := -g -O3
 CFLAGS-denano := -g -O2
 
 include $(MIPS_HOME)/make/compile.mk
diff --git a/make/mips_lib.mk b/make/mips_lib.mk
index da84262..cef0139 100644
--- a/make/mips_lib.mk
+++ b/make/mips_lib.mk
@@ -1,5 +1,5 @@
 CFLAGS-sim := -Os
-CFLAGS-ml402 := -g -O2
+CFLAGS-ml402 := -g -O3
 CFLAGS-denano := -g -O2
 
 include $(MIPS_HOME)/make/compile.mk