diff --git a/openbsc/src/abis_nm.c b/openbsc/src/abis_nm.c
index 31302f1..63d9d9c 100644
--- a/openbsc/src/abis_nm.c
+++ b/openbsc/src/abis_nm.c
@@ -1990,7 +1990,11 @@
 		for (i = 0; i < ts->hopping.arfcns.data_len*8; i++) {
 			if (bitvec_get_bit_pos(&ts->hopping.arfcns, i)) {
 				msgb_put_u16(msg, i);
-				*len += sizeof(uint16_t);
+				/* At least BS-11 wants a TLV16 here */
+				if (bts->type == GSM_BTS_TYPE_BS11)
+					*len += 1;
+				else
+					*len += sizeof(uint16_t);
 			}
 		}
 	}