diff --git a/src/data.c b/src/data.c
index 1f7efa5..82e99f0 100644
--- a/src/data.c
+++ b/src/data.c
@@ -228,10 +228,9 @@ int ptp_parse_prop_value(struct PtpRuntime *r) {
 		type = PTP_TC_UINT16; break;
 	case 4:
 		type = PTP_TC_UINT32; break;
-	case 0:
-		return -1;
 	default:
-		ptp_panic("ptp_parse_prop_value: unknown data type size %d", ptp_get_payload_length(r));
+		ptp_verbose_log("%s: unknown data type size %d - returning -1\n", __func__, ptp_get_payload_length(r));
+		return -1;
 	}
 
 	int out;
diff --git a/src/stuff.c b/src/stuff.c
index 151ec31..3df4fd5 100644
--- a/src/stuff.c
+++ b/src/stuff.c
@@ -22,5 +22,42 @@ int ptp_list_devices(void) {
 		printf("Model friendly name: '%s'\n", list->name);
 	}
 
+	ptp_close(r);
+
+	return 0;
+}
+
+static struct PtpRuntime *ptp_connect_id(int id) {
+	struct PtpRuntime *r = ptp_new(PTP_USB);
+	struct PtpDeviceEntry *list = ptpusb_device_list(r);
+
+	if (list == NULL) {
+		printf("No devices found\n");
+		return 0;
+	}
+
+	int i = 0;
+	for (; list != NULL; list = list->next) {
+		if (i == id) {
+			int rc = ptp_device_open(r, list);
+			if (rc) return NULL;
+			return r;
+		}
+		i++;
+	}
+
+	ptp_close(r);
+	return NULL;
+}
+
+int ptp_dump_device(void) {
+	struct PtpRuntime *r = ptp_connect_id(0);
+
+	struct PtpDeviceInfo di;
+	char buffer[4096];
+	ptp_get_device_info(r, &di);
+	ptp_device_info_json(&di, buffer, sizeof(buffer));
+	printf("%s\n", (char*)buffer);
+
 	return 0;
-}
\ No newline at end of file
+}
diff --git a/src/transport.c b/src/transport.c
index fd5868a..fa8c320 100644
--- a/src/transport.c
+++ b/src/transport.c
@@ -13,9 +13,15 @@ int ptp_send_packet(struct PtpRuntime *r, int length) {
 	int sent = 0;
 	while (1) {
 		int max = length - sent;
-		if (r->max_packet_size != 512) ptp_panic("max packet size is not 512, %d", r->max_packet_size);
 		if (max > r->max_packet_size) max = r->max_packet_size;
-		int rc = ptp_cmd_write(r, r->data + sent, max);
+		int rc;
+		if (r->connection_type == PTP_USB) {
+			rc = ptp_cmd_write(r, r->data + sent, max);
+		} else if (r->connection_type == PTP_IP_USB) {
+			rc = ptpip_cmd_write(r, r->data + sent, max);
+		} else {
+			ptp_panic("illegal connection_type");
+		}
 
 		if (rc < 0) {
 			ptp_verbose_log("%s: %d\n", __func__, rc);