diff --git a/include/osmocom/gprs/gprs_ns2.h b/include/osmocom/gprs/gprs_ns2.h
index cd2de96f4..6b88c7235 100644
--- a/include/osmocom/gprs/gprs_ns2.h
+++ b/include/osmocom/gprs/gprs_ns2.h
@@ -153,7 +153,7 @@ char *gprs_ns2_ll_str_c(const void *ctx, struct gprs_ns2_vc *nsvc);
 /* vty */
 int gprs_ns2_vty_init(struct gprs_ns2_inst *nsi);
 int gprs_ns2_vty_create();
-void gprs_ns2_vty_force_vc_mode(bool force, enum gprs_ns2_vc_mode mode, char *reason);
+void gprs_ns2_vty_force_vc_mode(bool force, enum gprs_ns2_vc_mode mode, const char *reason);
 
 
 /*! @} */
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
index ab869c347..9deb3a101 100644
--- a/src/gb/gprs_ns2_vty.c
+++ b/src/gb/gprs_ns2_vty.c
@@ -60,7 +60,7 @@ struct ns2_vty_priv {
 	/* force vc mode if another configuration forces
 	 * the vc mode. E.g. SNS configuration */
 	bool force_vc_mode;
-	char *force_vc_mode_reason;
+	const char *force_vc_mode_reason;
 	bool frgre;
 
 	struct llist_head vtyvc;
@@ -826,7 +826,7 @@ void ns2_vty_bind_apply(struct gprs_ns2_vc_bind *bind)
  * \param mode
  * \param reason A description shown to the user when a vty command wants to change the mode.
  */
-void gprs_ns2_vty_force_vc_mode(bool force, enum gprs_ns2_vc_mode mode, char *reason)
+void gprs_ns2_vty_force_vc_mode(bool force, enum gprs_ns2_vc_mode mode, const char *reason)
 {
 	priv.force_vc_mode = force;