diff --git a/Makefile.riscv64 b/Makefile.riscv64
index ce91e03ec..0246c0f7d 100644
--- a/Makefile.riscv64
+++ b/Makefile.riscv64
@@ -1,4 +1,4 @@
 ifeq ($(CORE), C910V)
-CCOMMON_OPT += -march=rv64imafdcv0p7_zfh_xtheadc -mabi=lp64d -mtune=c920
+CCOMMON_OPT += -march=rv64imafdcv0p7_zfh_xtheadc -mabi=lp64d -mtune=c920 -O1
 FCOMMON_OPT += -march=rv64imafdcv0p7_zfh_xtheadc -mabi=lp64d -mtune=c920 -static
 endif