diff --git a/build.sh b/build.sh
index 162e5979263abf9f48fd890f1ae3bd0b9e1da669..7601d05ca84568124f8de1334493fcd16a8aae16 100755
--- a/build.sh
+++ b/build.sh
@@ -2,6 +2,9 @@
 
 set -xe
 
+if [ -z ${SOURCE_DATE_EPOCH:+x} ] && git -C . rev-parse 2>/dev/null; then
+	export SOURCE_DATE_EPOCH=$(git log -1 --format=%ct)
+fi
 export CROSS_COMPILE=aarch64-linux-gnu-
 export ARCH=arm64
 export LDFLAGS=--no-warn-rwx-segments