diff --git a/sbin/camcontrol/camcontrol.c b/sbin/camcontrol/camcontrol.c
--- a/sbin/camcontrol/camcontrol.c
+++ b/sbin/camcontrol/camcontrol.c
@@ -3895,6 +3895,7 @@
 				warnx("invalid starting offset %s", optarg);
 				goto defect_bailout;
 			}
+			use_12byte = true;
 			break;
 		}
 		case 'X':