diff --git a/kernel/arm64/KERNEL b/kernel/arm64/KERNEL
index f936cdf47..7d7e648c4 100644
--- a/kernel/arm64/KERNEL
+++ b/kernel/arm64/KERNEL
@@ -1,3 +1,5 @@
+CSUMKERNEL=csum.S
+
 ifndef SNRM2KERNEL
 SNRM2KERNEL = ../arm/nrm2.c
 endif