diff --git a/openbsc/src/libbsc/bsc_vty.c b/openbsc/src/libbsc/bsc_vty.c
index b9519b4d0..e3ec8d9bf 100644
--- a/openbsc/src/libbsc/bsc_vty.c
+++ b/openbsc/src/libbsc/bsc_vty.c
@@ -2745,7 +2745,7 @@ DEFUN(cfg_bts_si2quater_neigh_add, cfg_bts_si2quater_neigh_add_cmd,
 	r = osmo_earfcn_add(e, arfcn, meas);
 
 	if (r < 0) {
-		vty_out(vty, "Unable to add arfcn %u: %s%s", arfcn, strerror(r),
+		vty_out(vty, "Unable to add arfcn %u: %s%s", arfcn, strerror(-r),
 			VTY_NEWLINE);
 		return CMD_WARNING;
 	}