diff --git a/src/gsm/lapd_core.c b/src/gsm/lapd_core.c
index 61fcc2f..5d4d801 100644
--- a/src/gsm/lapd_core.c
+++ b/src/gsm/lapd_core.c
@@ -1706,7 +1706,7 @@
 		rc = lapd_rx_i(msg, lctx);
 		break;
 	default:
-		LOGDL(lctx->dl, LOGL_NOTICE, "unknown LAPD format\n");
+		LOGDL(lctx->dl, LOGL_NOTICE, "unknown LAPD format 0x%02x\n", lctx->format);
 		msgb_free(msg);
 		rc = -EINVAL;
 	}