diff --git a/build-scripts/functions b/build-scripts/functions
index 769b8f55c..3f19b7a92 100644
--- a/build-scripts/functions
+++ b/build-scripts/functions
@@ -796,4 +796,11 @@ log_error() {
     echo "$(basename "$0"): error:" "$@" >&2
 }
 
+# Pin embedded build timestamps so two builds of the same source produce identical binaries.
+if [ -z "$SOURCE_DATE_EPOCH" ] && [ -d "$BASEDIR/core/.git" ]; then
+    SOURCE_DATE_EPOCH=$(git -C "$BASEDIR/core" log -1 --format=%ct)
+    export SOURCE_DATE_EPOCH
+    log_info "SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH"
+fi
+
 _IS_FUNCTIONS_SOURCED=yes