diff --git a/openbsc/src/libbsc/system_information.c b/openbsc/src/libbsc/system_information.c
index 69d2f7c..3f6d6b9 100644
--- a/openbsc/src/libbsc/system_information.c
+++ b/openbsc/src/libbsc/system_information.c
@@ -956,6 +956,7 @@
 		.t3192		= 1500,
 		.drx_timer_max	= 3,
 		.bs_cv_max	= 15,
+		.ctrl_ack_type_use_block = true,
 		.ext_info_present = 0,
 		.supports_egprs_11bit_rach = 0,
 		.ext_info = {
@@ -1003,6 +1004,9 @@
 	si13_default.no_pbcch.rac = bts->gprs.rac;
 	si13_default.no_pbcch.net_ctrl_ord = bts->gprs.net_ctrl_ord;
 
+	si13_default.cell_opts.ctrl_ack_type_use_block =
+		bts->gprs.ctrl_ack_type_use_block;
+
 	/* Information about the other SIs */
 	si13_default.bcch_change_mark = bts->bcch_change_mark;
 	si13_default.cell_opts.supports_egprs_11bit_rach =