diff --git a/src/backend.c b/src/backend.c
index 528ebb0..028c9a6 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1,5 +1,5 @@
-// Common IO backend code - only applies to platforms that have generic
-// USB packet IO access (Not Windows)
+// Packet stream read/write logic - uses bare I/O operations
+// Windows doesn't have that, so it can't be used here.
 
 // Copyright 2022 by Daniel C (https://github.com/petabyt/camlib)
 
diff --git a/src/canon.c b/src/canon.c
index c9d57c6..d65df4d 100644
--- a/src/canon.c
+++ b/src/canon.c
@@ -69,8 +69,6 @@ int ptp_eos_get_viewfinder_data(struct PtpRuntime *r) {
 	cmd.param_length = 1;
 
 	cmd.params[0] = 0x200000;
-	cmd.params[1] = 0x0;
-	cmd.params[2] = 0x0;
 
 	return ptp_generic_send(r, &cmd);
 }
diff --git a/src/ip.c b/src/ip.c
index d5cdcd9..722e8b0 100644
--- a/src/ip.c
+++ b/src/ip.c
@@ -1,4 +1,4 @@
-// PTP/IP implementation - 
+// POSIX PTP/IP implementation
 // Copyright 2023 by Daniel C (https://github.com/petabyt/camlib)
 
 #include <stdio.h>
diff --git a/src/libwpd.c b/src/libwpd.c
index 5b10eb3..ab7ffdb 100644
--- a/src/libwpd.c
+++ b/src/libwpd.c
@@ -1,3 +1,5 @@
+// Windows USB I/O frontend for libwpd (https://github.com/petabyt/libwpd)
+// Copyright 2022 by Daniel C (https://github.com/petabyt/camlib)
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -9,9 +11,16 @@
 
 struct WpdStruct backend_wpd;
 
-int ptp_device_init(struct PtpRuntime *r) {
+int ptp_comm_init(struct PtpRuntime *r) {
 	ptp_generic_reset(r);
 	wpd_init(1, L"Camlib WPD");
+
+	return 0;	
+}
+
+int ptp_device_init(struct PtpRuntime *r) {
+	ptp_comm_init();
+
 	int length = 0;
 	wchar_t **devices = wpd_get_devices(&backend_wpd, &length);
 
@@ -37,6 +46,14 @@ int ptp_device_init(struct PtpRuntime *r) {
 	return PTP_NO_DEVICE;
 }
 
+struct PtpDeviceEntry *ptpusb_device_list(struct PtpRuntime *r) {
+	return NULL;
+}
+
+int ptp_device_open(struct PtpRuntime *r, struct PtpDeviceEntry *entry) {
+	return PTP_IO_ERR;
+}
+
 int ptp_send_bulk_packets(struct PtpRuntime *r, int length) {
 	struct PtpCommand cmd;
 	struct PtpBulkContainer *bulk = (struct PtpBulkContainer*)(r->data);
@@ -121,7 +138,7 @@ int ptp_receive_bulk_packets(struct PtpRuntime *r) {
 	return 0;
 }
 
-int ptp_receive_int(void *to, int length) {
+int ptp_read_int(void *to, int length) {
 	return 0;
 }
 
diff --git a/src/no_ip.c b/src/no_ip.c
new file mode 100644
index 0000000..45c5f74
--- /dev/null
+++ b/src/no_ip.c
@@ -0,0 +1,36 @@
+// Include this if you wish to never use TCP/IP
+// Copyright 2022 by Daniel C (https://github.com/petabyt/camlib)
+#include <camlib.h>
+#include <ptp.h>
+
+int ptpip_new_timeout_socket(char *addr, int port) {
+	return -1;	
+}
+
+int ptpip_connect(struct PtpRuntime *r, char *addr, int port) {
+	return -1;
+}
+
+int ptpip_connect_events(struct PtpRuntime *r, char *addr, int port) {
+	return -1;
+}
+
+int ptpip_close(struct PtpRuntime *r) {
+	return -1;
+}
+
+int ptpip_cmd_write(struct PtpRuntime *r, void *data, int size) {
+	return -1;
+}
+
+int ptpip_cmd_read(struct PtpRuntime *r, void *data, int size) {
+	return -1;
+}
+
+int ptpip_event_send(struct PtpRuntime *r, void *data, int size) {
+	return -1;
+}
+
+int ptpip_event_read(struct PtpRuntime *r, void *data, int size) {
+	return -1;
+}
diff --git a/src/pack.c b/src/pack.c
new file mode 100644
index 0000000..b6619b6
--- /dev/null
+++ b/src/pack.c
@@ -0,0 +1,9 @@
+#include <camlib.h>
+
+int ptp_pack_fuji_object_info(struct PtpRuntime *r, struct PtpObjectInfo *oi, void *buffer, int max) {
+	void **ptr = (void **)(&buffer);
+
+	memcpy(*ptr, oi, PTP_FUJI_OBJ_INFO_VAR_START);
+	(*ptr) += PTP_FUJI_OBJ_INFO_VAR_START;
+
+}
diff --git a/src/ptp.h b/src/ptp.h
index 7f63216..6a2473a 100644
--- a/src/ptp.h
+++ b/src/ptp.h
@@ -660,6 +660,8 @@ struct PtpIpEndDataPacket {
 // See https://en.wikipedia.org/wiki/USB#Device_classes
 #define PTP_CLASS_ID 6
 
+#define USB_VENDOR_CANON 0x4A9
+
 // ISO number for PTP/IP, seems to be standard (?)
 #define PTP_IP_PORT 15740
 
diff --git a/src/util.c b/src/util.c
index 1cf8c00..cf1b2bf 100644
--- a/src/util.c
+++ b/src/util.c
@@ -128,7 +128,7 @@ int ptp_generic_send_data(struct PtpRuntime *r, struct PtpCommand *cmd, void *da
 	} else {
 		// Single data packet
 		plength = ptp_new_data_packet(r, cmd, data, length);
-		if (ptp_send_bulk_packets(r, plength) != plength) {
+		if (ptp_send_bulk_packets(r, plength) != plength + length) {
 			ptp_mutex_unlock(r);
 			return PTP_IO_ERR;
 		}
@@ -157,8 +157,7 @@ struct UintArray *ptp_dup_uint_array(struct UintArray *arr) {
 	return arr2;
 }
 
-// May be slightly inneficient for every frame/action
-// TODO: maybe 'cache' dev type for speed
+// TODO: maybe 'cache' dev type
 int ptp_device_type(struct PtpRuntime *r) {
 	struct PtpDeviceInfo *di = r->di;
 	if (di == NULL) return PTP_DEV_EMPTY;