diff --git a/lib/tiny-cloud/user-data/alpine-config b/lib/tiny-cloud/user-data/alpine-config
index def1b1f..63e10ca 100644
--- a/lib/tiny-cloud/user-data/alpine-config
+++ b/lib/tiny-cloud/user-data/alpine-config
@@ -71,7 +71,7 @@ init__userdata_autoinstall() {
 		if [ -n "$disk" ]; then
 			rm -f "$ETC"/runlevels/*/tiny-cloud*
 			$MOCK lbu include /root/.ssh /home
-			$MOCK ERASE_DISKS=/dev/$disk setup-disk -m sys /dev/$disk
+			ERASE_DISKS=/dev/$disk $MOCK setup-disk -m sys /dev/$disk
 			# TODO: make reboot configurable
 			$MOCK reboot
 		else