diff --git a/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc b/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc
index 12f32ff0..125554e1 100644
--- a/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc
+++ b/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc
@@ -34,7 +34,7 @@ DISTRO_VARS_PREFIX ?= "${@'HOST_' if bb.utils.to_boolean(d.getVar('BOOTSTRAP_FOR
 BOOTSTRAP_DISTRO = "${@d.getVar('HOST_DISTRO' if bb.utils.to_boolean(d.getVar('BOOTSTRAP_FOR_HOST')) else 'DISTRO')}"
 BOOTSTRAP_BASE_DISTRO = "${@d.getVar('HOST_BASE_DISTRO' if bb.utils.to_boolean(d.getVar('BOOTSTRAP_FOR_HOST')) else 'BASE_DISTRO')}"
 FILESEXTRAPATHS:append = ":${BBPATH}"
-APT_SNAPSHOT_DATE = "${@ get_apt_snapshot_date(d)}"
+APT_SNAPSHOT_DATE ?= "${@ get_apt_snapshot_date(d)}"
 
 inherit deb-dl-dir