diff --git a/camlibs/ptp/library.c b/camlibs/ptp/library.c
index 2cfb24bce..709f63ffa 100644
--- a/camlibs/ptp/library.c
+++ b/camlibs/ptp/library.c
@@ -1029,15 +1029,6 @@ camera_init (Camera *camera, GPContext *context)
 	/* Use the defaults the core parsed */
 	CR (gp_port_set_settings (camera->port, settings));
 
-	/* get device info */
-	CPR(context, ptp_getdeviceinfo(&camera->pl->params,
-	&camera->pl->params.deviceinfo));
-
-	GP_DEBUG ("Vendor extension description: %s",camera->pl->params.deviceinfo.VendorExtensionDesc);
-	GP_DEBUG ("Manufacturer: %s",camera->pl->params.deviceinfo.Manufacturer);
-	GP_DEBUG ("  model: %s", camera->pl->params.deviceinfo.Model);
-	GP_DEBUG ("  device version: %s", camera->pl->params.deviceinfo.DeviceVersion);
-
 	/* Establish a connection to the camera */
 	((PTPData *) camera->pl->params.data)->context = context;
 	ret=ptp_opensession (&camera->pl->params, 1);
@@ -1050,6 +1041,16 @@ camera_init (Camera *camera, GPContext *context)
 		return (translate_ptp_result(ret));
 	}
 
+	/* Seems HP does not like getdevinfo outside of session */
+	/* get device info */
+	CPR(context, ptp_getdeviceinfo(&camera->pl->params,
+	&camera->pl->params.deviceinfo));
+
+	GP_DEBUG ("Vendor extension description: %s",camera->pl->params.deviceinfo.VendorExtensionDesc);
+	GP_DEBUG ("Manufacturer: %s",camera->pl->params.deviceinfo.Manufacturer);
+	GP_DEBUG ("  model: %s", camera->pl->params.deviceinfo.Model);
+	GP_DEBUG ("  device version: %s", camera->pl->params.deviceinfo.DeviceVersion);
+
 	/* init internal ptp objectfiles (required for fs implementation) */
 	init_ptp_fs (camera, context);
 
diff --git a/camlibs/ptp/ptp.h b/camlibs/ptp/ptp.h
index 7ced27531..ac96ea72a 100644
--- a/camlibs/ptp/ptp.h
+++ b/camlibs/ptp/ptp.h
@@ -34,7 +34,7 @@
 
 #define PTP_REQ_LEN			30
 #define PTP_RESP_LEN			sizeof(PTPReq)
-#define PTP_REQ_HDR_LEN                 (3*sizeof(uint32_t)+2*sizeof(uint16_t))
+#define PTP_REQ_HDR_LEN                 (2*sizeof(uint32_t)+2*sizeof(uint16_t))
 #define PTP_REQ_DATALEN			16384
 #define PTP_EVENT_LEN			sizeof(PTPEvent)
 
@@ -42,7 +42,6 @@ struct _PTPReq {
 	uint32_t len;
 	uint16_t type;
 	uint16_t code;
-	uint32_t session_id;
 	uint32_t trans_id;
 	char data[PTP_REQ_DATALEN];
 };