diff --git a/openbsc/src/osmo-nitb/bsc_hack.c b/openbsc/src/osmo-nitb/bsc_hack.c
index dd90b8b..d8029cd 100644
--- a/openbsc/src/osmo-nitb/bsc_hack.c
+++ b/openbsc/src/osmo-nitb/bsc_hack.c
@@ -301,6 +301,20 @@
 	} else
 		DEBUGP(DMNCC, "Using internal MNCC handler.\n");
 
+	/*
+	 * For osmo-nitb, skip TCH/F for now, because otherwise dyn TS
+	 * always imply the possibility to have a mix of TCH/F and
+	 * TCH/H channels; if two phones request a TCH/F and a TCH/H,
+	 * respectively, they cannot call each other. If we deny TCH/F,
+	 * they will both fall back to TCH/H, and dynamic channels are
+	 * usable. See OS#1778.
+	 *
+	 * A third-party MSC may well be able to handle a TCH/H TCH/F
+	 * mismatch. Moreover, this option may be overwritten in the
+	 * config file or in VTY.
+	 */
+	bsc_gsmnet->dyn_ts_allow_tch_f = false;
+
 	/* Read the config */
 	rc = bsc_network_configure(config_file);
 	if (rc < 0) {
@@ -313,19 +327,6 @@
 #endif
 	bsc_api_init(bsc_gsmnet, msc_bsc_api());
 
-	/*
-	 * For osmo-nitb, skip TCH/F for now, because otherwise dyn TS
-	 * always imply the possibility to have a mix of TCH/F and
-	 * TCH/H channels; if two phones request a TCH/F and a TCH/H,
-	 * respectively, they cannot call each other. If we deny TCH/F,
-	 * they will both fall back to TCH/H, and dynamic channels are
-	 * usable. See http://osmocom.org/issues/1778.
-	 *
-	 * A third-party MSC may well be able to handle a TCH/H TCH/F
-	 * mismatch.
-	 */
-	bsc_gsmnet->dyn_ts_allow_tch_f = false;
-
 	/* start control interface after reading config for
 	 * ctrl_vty_get_bind_addr() */
 	bsc_gsmnet->ctrl = bsc_controlif_setup(bsc_gsmnet,