diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 6bdc988471..36c384fed9 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -7051,10 +7051,12 @@ static int sip_hangup(struct ast_channel *ast)
 		ast_debug(4, "SIP Transfer: Not hanging up right now... Rescheduling hangup for %s.\n", p->callid);
 		sip_scheddestroy(p, DEFAULT_TRANS_TIMEOUT);
 		ast_clear_flag(&p->flags[0], SIP_DEFER_BYE_ON_TRANSFER);	/* Really hang up next time */
-		ast_channel_tech_pvt_set(p->owner, dialog_unref(ast_channel_tech_pvt(p->owner), "unref p->owner->tech_pvt"));
-		sip_pvt_lock(p);
-		p->owner = NULL;  /* Owner will be gone after we return, so take it away */
-		sip_pvt_unlock(p);
+		if (p->owner) {
+			ast_channel_tech_pvt_set(p->owner, dialog_unref(ast_channel_tech_pvt(p->owner), "unref p->owner->tech_pvt"));
+			sip_pvt_lock(p);
+			p->owner = NULL;  /* Owner will be gone after we return, so take it away */
+			sip_pvt_unlock(p);
+		}
 		ast_module_unref(ast_module_info->self);
 		return 0;
 	}
@@ -7083,7 +7085,7 @@ static int sip_hangup(struct ast_channel *ast)
 
 	stop_media_flows(p); /* Immediately stop RTP, VRTP and UDPTL as applicable */
 
-	append_history(p, needcancel ? "Cancel" : "Hangup", "Cause %s", p->owner ? ast_cause2str(p->hangupcause) : "Unknown");
+	append_history(p, needcancel ? "Cancel" : "Hangup", "Cause %s", ast_cause2str(p->hangupcause));
 
 	/* Disconnect */
 	disable_dsp_detect(p);
@@ -7585,7 +7587,9 @@ static int interpret_t38_parameters(struct sip_pvt *p, const struct ast_control_
 			AST_SCHED_DEL_UNREF(sched, p->t38id, dialog_unref(p, "when you delete the t38id sched, you should dec the refcount for the stored dialog ptr"));
 			parameters.max_ifp = ast_udptl_get_far_max_ifp(p->udptl);
 			parameters.request_response = AST_T38_REQUEST_NEGOTIATE;
-			ast_queue_control_data(p->owner, AST_CONTROL_T38_PARAMETERS, &parameters, sizeof(parameters));
+			if (p->owner) {
+				ast_queue_control_data(p->owner, AST_CONTROL_T38_PARAMETERS, &parameters, sizeof(parameters));
+			}
 			/* we need to return a positive value here, so that applications that
 			 * send this request can determine conclusively whether it was accepted or not...
 			 * older versions of chan_sip would just silently accept it and return zero.
@@ -12506,9 +12510,9 @@ static int add_rpid(struct sip_request *req, struct sip_pvt *p)
 {
 	struct ast_str *tmp = ast_str_alloca(256);
 	char tmp2[256];
-	char *lid_num = NULL;
-	char *lid_name = NULL;
-	int lid_pres = AST_PRES_NUMBER_NOT_AVAILABLE;
+	char *lid_num;
+	char *lid_name;
+	int lid_pres;
 	const char *fromdomain;
 	const char *privacy = NULL;
 	const char *screen = NULL;
@@ -12519,22 +12523,20 @@ static int add_rpid(struct sip_request *req, struct sip_pvt *p)
 		return 0;
 	}
 
-	if (p->owner) {
-		connected_id = ast_channel_connected_effective_id(p->owner);
-
-		if (connected_id.number.valid) {
-			lid_num = connected_id.number.str;
-		}
-		if (connected_id.name.valid) {
-			lid_name = connected_id.name.str;
-		}
-		lid_pres = ast_party_id_presentation(&connected_id);
+	if (!p->owner) {
+		return 0;
 	}
-
-	if (ast_strlen_zero(lid_num))
+	connected_id = ast_channel_connected_effective_id(p->owner);
+	lid_num = S_COR(connected_id.number.valid, connected_id.number.str, NULL);
+	if (!lid_num) {
 		return 0;
-	if (ast_strlen_zero(lid_name))
+	}
+	lid_name = S_COR(connected_id.name.valid, connected_id.name.str, NULL);
+	if (!lid_name) {
 		lid_name = lid_num;
+	}
+	lid_pres = ast_party_id_presentation(&connected_id);
+
 	fromdomain = S_OR(p->fromdomain, ast_sockaddr_stringify_host_remote(&p->ourip));
 
 	lid_num = ast_uri_encode(lid_num, tmp2, sizeof(tmp2), ast_uri_sip_user);
@@ -17897,13 +17899,15 @@ static int get_refer_info(struct sip_pvt *transferer, struct sip_request *outgoi
 	}
 
 	/* Determine transfer context */
-	if (transferer->owner)	/* Mimic behaviour in res_features.c */
+	if (transferer->owner) {
+		/* By default, use the context in the channel sending the REFER */
 		transfer_context = pbx_builtin_getvar_helper(transferer->owner, "TRANSFER_CONTEXT");
-
-	/* By default, use the context in the channel sending the REFER */
+		if (ast_strlen_zero(transfer_context)) {
+			transfer_context = ast_channel_macrocontext(transferer->owner);
+		}
+	}
 	if (ast_strlen_zero(transfer_context)) {
-		transfer_context = S_OR(ast_channel_macrocontext(transferer->owner),
-					S_OR(transferer->context, sip_cfg.default_context));
+		transfer_context = S_OR(transferer->context, sip_cfg.default_context);
 	}
 
 	ast_string_field_set(refer, refer_to_context, transfer_context);
@@ -17957,14 +17961,18 @@ static int get_also_info(struct sip_pvt *p, struct sip_request *oreq)
 	if (sip_debug_test_pvt(p))
 		ast_verbose("Looking for %s in %s\n", c, p->context);
 
-	if (p->owner)	/* Mimic behaviour in res_features.c */
+	/* Determine transfer context */
+	if (p->owner) {
+		/* By default, use the context in the channel sending the REFER */
 		transfer_context = pbx_builtin_getvar_helper(p->owner, "TRANSFER_CONTEXT");
-
-	/* By default, use the context in the channel sending the REFER */
+		if (ast_strlen_zero(transfer_context)) {
+			transfer_context = ast_channel_macrocontext(p->owner);
+		}
+	}
 	if (ast_strlen_zero(transfer_context)) {
-		transfer_context = S_OR(ast_channel_macrocontext(p->owner),
-					S_OR(p->context, sip_cfg.default_context));
+		transfer_context = S_OR(p->context, sip_cfg.default_context);
 	}
+
 	if (ast_exists_extension(NULL, transfer_context, c, 1, NULL)) {
 		/* This is a blind transfer */
 		ast_debug(1, "SIP Bye-also transfer to Extension %s@%s \n", c, transfer_context);
@@ -25455,12 +25463,6 @@ static int handle_request_invite(struct sip_pvt *p, struct sip_request *req, str
 			ast_debug(2, "No SDP in Invite, third party call control\n");
 		}
 
-		/* Queue NULL frame to prod ast_rtp_bridge if appropriate */
-		/* This seems redundant ... see !p-owner above */
-		if (p->owner)
-			ast_queue_frame(p->owner, &ast_null_frame);
-
-
 		/* Initialize the context if it hasn't been already */
 		if (ast_strlen_zero(p->context))
 			ast_string_field_set(p, context, sip_cfg.default_context);
@@ -29953,7 +29955,7 @@ static struct ast_channel *sip_request_call(const char *type, struct ast_format_
 	if (sip_cfg.callevents)
 		manager_event(EVENT_FLAG_SYSTEM, "ChannelUpdate",
 			"Channel: %s\r\nChanneltype: %s\r\nSIPcallid: %s\r\nSIPfullcontact: %s\r\nPeername: %s\r\n",
-			p->owner? ast_channel_name(p->owner) : "", "SIP", p->callid, p->fullcontact, p->peername);
+			p->owner ? ast_channel_name(p->owner) : "", "SIP", p->callid, p->fullcontact, p->peername);
 	sip_pvt_unlock(p);
 	if (!tmpc) {
 		dialog_unlink_all(p);