diff --git a/Source/hoc-clk/overlay/Makefile b/Source/hoc-clk/overlay/Makefile
index 67ed2c13..331a6617 100644
--- a/Source/hoc-clk/overlay/Makefile
+++ b/Source/hoc-clk/overlay/Makefile
@@ -49,7 +49,7 @@ DEFINES := -DDISABLE_IPC -DTARGET="\"$(TARGET)\"" -DTARGET_VERSION="\"$(TARGET_V
 
 ARCH	:=	-march=armv8-a+crc+crypto -mtune=cortex-a57 -mtp=soft -fPIE
 
-CFLAGS	:=	-O2 -Wall -flto -fdata-sections -ffunction-sections -fno-rtti -fno-common \
+CFLAGS	:=	-Os -Wall -flto -fdata-sections -ffunction-sections -fno-rtti -fno-common \
 			$(ARCH) $(DEFINES)
 
 CFLAGS	+=	$(INCLUDE) -D__SWITCH__