diff --git a/tools/thermal/tmon/Makefile b/tools/thermal/tmon/Makefile
index 89a2444c1df263a9a29df0c5b84bf14bdf0951c0..59e417ec3e134ce48fd039662d5b7bf6d49bba52 100644
--- a/tools/thermal/tmon/Makefile
+++ b/tools/thermal/tmon/Makefile
@@ -6,7 +6,7 @@ VERSION = 1.0
 
 BINDIR=usr/bin
 WARNFLAGS=-Wall -Wshadow -W -Wformat -Wimplicit-function-declaration -Wimplicit-int
-override CFLAGS+= -O1 ${WARNFLAGS}
+override CFLAGS+= $(call cc-option,-O3,-O1) ${WARNFLAGS}
 # Add "-fstack-protector" only if toolchain supports it.
 override CFLAGS+= $(call cc-option,-fstack-protector-strong)
 CC?= $(CROSS_COMPILE)gcc