diff --git a/openbsc/src/libcommon/gsm_data.c b/openbsc/src/libcommon/gsm_data.c
index 9d794ee..75475db 100644
--- a/openbsc/src/libcommon/gsm_data.c
+++ b/openbsc/src/libcommon/gsm_data.c
@@ -315,6 +315,7 @@
 	bts->bsic = bsic;
 	bts->dtxu = GSM48_DTX_SHALL_NOT_BE_USED;
 	bts->dtxd = false;
+	bts->gprs.ctrl_ack_type_use_block = true; /* use RLC/MAC control block */
 	bts->neigh_list_manual_mode = 0;
 	bts->si_common.cell_sel_par.cell_resel_hyst = 2; /* 4 dB */
 	bts->si_common.cell_sel_par.rxlev_acc_min = 0;