diff --git a/Source/HBIOS/ch376-native/base-drv/ch376.c.s b/Source/HBIOS/ch376-native/base-drv/ch376.c.s
index 54dde6cc..35d7c3cb 100644
--- a/Source/HBIOS/ch376-native/base-drv/ch376.c.s
+++ b/Source/HBIOS/ch376-native/base-drv/ch376.c.s
@@ -251,7 +251,7 @@ l_ch_probe_00107:
 	inc	sp
 	pop	ix
 	ret
-;source-doc/base-drv/ch376.c:112: uint8_t ch_cmd_set_usb_mode(const uint8_t mode) __z88dk_fastcall {
+;source-doc/base-drv/ch376.c:112: usb_error ch_cmd_set_usb_mode(const uint8_t mode) __z88dk_fastcall {
 ; ---------------------------------
 ; Function ch_cmd_set_usb_mode
 ; ---------------------------------
@@ -581,7 +581,7 @@ l_ch_data_in_transfer_00111:
 ;source-doc/base-drv/ch376.c:187: }
 	pop	ix
 	ret
-;source-doc/base-drv/ch376.c:190: usb_error ch_data_in_transfer_n(uint8_t *const buffer, int8_t *const buffer_size, endpoint_param *const endpoint) {
+;source-doc/base-drv/ch376.c:190: usb_error ch_data_in_transfer_n(uint8_t *const buffer, uint8_t *const buffer_size, endpoint_param *const endpoint) {
 ; ---------------------------------
 ; Function ch_data_in_transfer_n
 ; ---------------------------------
diff --git a/Source/HBIOS/ch376-native/base-drv/dev_transfers.c.s b/Source/HBIOS/ch376-native/base-drv/dev_transfers.c.s
index 3060aa9c..baa56e99 100644
--- a/Source/HBIOS/ch376-native/base-drv/dev_transfers.c.s
+++ b/Source/HBIOS/ch376-native/base-drv/dev_transfers.c.s
@@ -48,7 +48,7 @@ _USB_MODULE_LEDS	.EQU	0xff8a
 ;--------------------------------------------------------
 ; code
 ;--------------------------------------------------------
-;source-doc/base-drv/dev_transfers.c:24: * See https://www.beyondlogic.org/usbnutshell/usb4.shtml for a description of the USB control transfer
+;source-doc/base-drv/dev_transfers.c:23: * See https://www.beyondlogic.org/usbnutshell/usb4.shtml for a description of the USB control transfer
 ; ---------------------------------
 ; Function usbdev_control_transfer
 ; ---------------------------------
@@ -56,7 +56,7 @@ _usbdev_control_transfer:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/dev_transfers.c:25: *
+;source-doc/base-drv/dev_transfers.c:24: *
 	ld	l,(ix+4)
 	ld	h,(ix+5)
 	ld	e,l
@@ -82,10 +82,10 @@ _usbdev_control_transfer:
 	pop	af
 	pop	af
 	pop	af
-;source-doc/base-drv/dev_transfers.c:26: * @param device the usb device
+;source-doc/base-drv/dev_transfers.c:25: * @param device the usb device
 	pop	ix
 	ret
-;source-doc/base-drv/dev_transfers.c:28: * @param buffer Pointer of data to send or receive into
+;source-doc/base-drv/dev_transfers.c:27: * @param buffer Pointer of data to send or receive into
 ; ---------------------------------
 ; Function usbdev_blk_out_trnsfer
 ; ---------------------------------
@@ -95,13 +95,13 @@ _usbdev_blk_out_trnsfer:
 	add	ix,sp
 	push	af
 	push	af
-;source-doc/base-drv/dev_transfers.c:30: */
+;source-doc/base-drv/dev_transfers.c:29: */
 	ld	e,(ix+4)
 	ld	d,(ix+5)
 	ld	hl,0x0003
 	add	hl, de
 	ex	(sp), hl
-;source-doc/base-drv/dev_transfers.c:32: return usb_control_transfer(cmd_packet, buffer, device->address, device->max_packet_size);
+;source-doc/base-drv/dev_transfers.c:31: return usb_control_transfer(cmd_packet, buffer, device->address, device->max_packet_size);
 	ld	(ix-2),e
 	ld	(ix-1),d
 	pop	bc
@@ -134,12 +134,12 @@ _usbdev_blk_out_trnsfer:
 	pop	de
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/dev_transfers.c:34:
+;source-doc/base-drv/dev_transfers.c:33:
 	ld	hl,_result
 	ld	a, (hl)
 	sub	0x02
 	jr	NZ,l_usbdev_blk_out_trnsfer_00102
-;source-doc/base-drv/dev_transfers.c:35: usb_error usbdev_blk_out_trnsfer(device_config *const dev, const uint8_t *const buffer, const uint16_t buffer_size) {
+;source-doc/base-drv/dev_transfers.c:34: usb_error usbdev_blk_out_trnsfer(device_config *const dev, const uint8_t *const buffer, const uint16_t buffer_size) {
 	ex	de, hl
 	inc	hl
 	ld	d, (hl)
@@ -164,23 +164,23 @@ _usbdev_blk_out_trnsfer:
 	call	_usbtrn_clear_endpoint_halt
 	pop	af
 	inc	sp
-;source-doc/base-drv/dev_transfers.c:36:
+;source-doc/base-drv/dev_transfers.c:35:
 	pop	hl
 	push	hl
 	res	0, (hl)
-;source-doc/base-drv/dev_transfers.c:37: endpoint_param *const endpoint = &dev->endpoints[ENDPOINT_BULK_OUT];
+;source-doc/base-drv/dev_transfers.c:36: endpoint_param *const endpoint = &dev->endpoints[ENDPOINT_BULK_OUT];
 	ld	l,0x02
 	jr	l_usbdev_blk_out_trnsfer_00104
 l_usbdev_blk_out_trnsfer_00102:
-;source-doc/base-drv/dev_transfers.c:40:
-;source-doc/base-drv/dev_transfers.c:43: endpoint->toggle = 0;
+;source-doc/base-drv/dev_transfers.c:39:
+;source-doc/base-drv/dev_transfers.c:42: endpoint->toggle = 0;
 	ld	hl, (_result)
 l_usbdev_blk_out_trnsfer_00104:
-;source-doc/base-drv/dev_transfers.c:44: return USB_ERR_STALL;
+;source-doc/base-drv/dev_transfers.c:43: return USB_ERR_STALL;
 	ld	sp, ix
 	pop	ix
 	ret
-;source-doc/base-drv/dev_transfers.c:46:
+;source-doc/base-drv/dev_transfers.c:45:
 ; ---------------------------------
 ; Function usbdev_bulk_in_transfer
 ; ---------------------------------
@@ -190,13 +190,13 @@ _usbdev_bulk_in_transfer:
 	add	ix,sp
 	push	af
 	push	af
-;source-doc/base-drv/dev_transfers.c:47: RETURN_CHECK(result);
+;source-doc/base-drv/dev_transfers.c:46: RETURN_CHECK(result);
 	ld	e,(ix+4)
 	ld	d,(ix+5)
 	ld	hl,0x0006
 	add	hl, de
 	ex	(sp), hl
-;source-doc/base-drv/dev_transfers.c:49: done:
+;source-doc/base-drv/dev_transfers.c:48: done:
 	ld	(ix-2),e
 	ld	(ix-1),d
 	pop	bc
@@ -229,12 +229,12 @@ _usbdev_bulk_in_transfer:
 	pop	de
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/dev_transfers.c:51: }
+;source-doc/base-drv/dev_transfers.c:50: }
 	ld	hl,_result
 	ld	a, (hl)
 	sub	0x02
 	jr	NZ,l_usbdev_bulk_in_transfer_00102
-;source-doc/base-drv/dev_transfers.c:52:
+;source-doc/base-drv/dev_transfers.c:51:
 	ex	de, hl
 	inc	hl
 	ld	d, (hl)
@@ -259,23 +259,23 @@ _usbdev_bulk_in_transfer:
 	call	_usbtrn_clear_endpoint_halt
 	pop	af
 	inc	sp
-;source-doc/base-drv/dev_transfers.c:53: usb_error usbdev_bulk_in_transfer(device_config *const dev, uint8_t *const buffer, uint8_t *const buffer_size) {
+;source-doc/base-drv/dev_transfers.c:52: usb_error usbdev_bulk_in_transfer(device_config *const dev, uint8_t *const buffer, uint8_t *const buffer_size) {
 	pop	hl
 	push	hl
 	res	0, (hl)
-;source-doc/base-drv/dev_transfers.c:54: endpoint_param *const endpoint = &dev->endpoints[ENDPOINT_BULK_IN];
+;source-doc/base-drv/dev_transfers.c:53: endpoint_param *const endpoint = &dev->endpoints[ENDPOINT_BULK_IN];
 	ld	l,0x02
 	jr	l_usbdev_bulk_in_transfer_00104
 l_usbdev_bulk_in_transfer_00102:
-;source-doc/base-drv/dev_transfers.c:57:
-;source-doc/base-drv/dev_transfers.c:59: usbtrn_clear_endpoint_halt(endpoint->number, dev->address, dev->max_packet_size);
+;source-doc/base-drv/dev_transfers.c:56:
+;source-doc/base-drv/dev_transfers.c:58: usbtrn_clear_endpoint_halt(endpoint->number, dev->address, dev->max_packet_size);
 	ld	hl, (_result)
 l_usbdev_bulk_in_transfer_00104:
-;source-doc/base-drv/dev_transfers.c:60: endpoint->toggle = 0;
+;source-doc/base-drv/dev_transfers.c:59: endpoint->toggle = 0;
 	ld	sp, ix
 	pop	ix
 	ret
-;source-doc/base-drv/dev_transfers.c:62: }
+;source-doc/base-drv/dev_transfers.c:61: }
 ; ---------------------------------
 ; Function usbdev_dat_in_trnsfer
 ; ---------------------------------
@@ -285,7 +285,7 @@ _usbdev_dat_in_trnsfer:
 	add	ix,sp
 	push	af
 	push	af
-;source-doc/base-drv/dev_transfers.c:67: }
+;source-doc/base-drv/dev_transfers.c:66: }
 	ld	e,(ix+4)
 	ld	d,(ix+5)
 	ld	c, e
@@ -304,7 +304,7 @@ _usbdev_dat_in_trnsfer:
 	ld	a,0x00
 	adc	a, b
 	ld	(ix-3),a
-;source-doc/base-drv/dev_transfers.c:69: usb_error usbdev_dat_in_trnsfer(device_config *const    device,
+;source-doc/base-drv/dev_transfers.c:68: usb_error usbdev_dat_in_trnsfer(device_config *const    device,
 	ld	(ix-2),e
 	ld	(ix-1),d
 	pop	bc
@@ -337,12 +337,12 @@ _usbdev_dat_in_trnsfer:
 	pop	de
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/dev_transfers.c:71: const uint16_t          buffer_size,
+;source-doc/base-drv/dev_transfers.c:70: const uint16_t          buffer_size,
 	ld	hl,_result
 	ld	a, (hl)
 	sub	0x02
 	jr	NZ,l_usbdev_dat_in_trnsfer_00102
-;source-doc/base-drv/dev_transfers.c:72: const usb_endpoint_type endpoint_type) {
+;source-doc/base-drv/dev_transfers.c:71: const usb_endpoint_type endpoint_type) {
 	ex	de, hl
 	inc	hl
 	ld	d, (hl)
@@ -367,23 +367,23 @@ _usbdev_dat_in_trnsfer:
 	call	_usbtrn_clear_endpoint_halt
 	pop	af
 	inc	sp
-;source-doc/base-drv/dev_transfers.c:73:
+;source-doc/base-drv/dev_transfers.c:72:
 	pop	hl
 	push	hl
 	res	0, (hl)
-;source-doc/base-drv/dev_transfers.c:74: endpoint_param *const endpoint = &device->endpoints[endpoint_type];
+;source-doc/base-drv/dev_transfers.c:73: endpoint_param *const endpoint = &device->endpoints[endpoint_type];
 	ld	l,0x02
 	jr	l_usbdev_dat_in_trnsfer_00104
 l_usbdev_dat_in_trnsfer_00102:
-;source-doc/base-drv/dev_transfers.c:77:
-;source-doc/base-drv/dev_transfers.c:79: usbtrn_clear_endpoint_halt(endpoint->number, device->address, device->max_packet_size);
+;source-doc/base-drv/dev_transfers.c:76:
+;source-doc/base-drv/dev_transfers.c:78: usbtrn_clear_endpoint_halt(endpoint->number, device->address, device->max_packet_size);
 	ld	hl, (_result)
 l_usbdev_dat_in_trnsfer_00104:
-;source-doc/base-drv/dev_transfers.c:80: endpoint->toggle = 0;
+;source-doc/base-drv/dev_transfers.c:79: endpoint->toggle = 0;
 	ld	sp, ix
 	pop	ix
 	ret
-;source-doc/base-drv/dev_transfers.c:82: }
+;source-doc/base-drv/dev_transfers.c:81: }
 ; ---------------------------------
 ; Function usbdev_dat_in_trnsfer_0
 ; ---------------------------------
@@ -393,13 +393,13 @@ _usbdev_dat_in_trnsfer_0:
 	add	ix,sp
 	push	af
 	push	af
-;source-doc/base-drv/dev_transfers.c:83:
+;source-doc/base-drv/dev_transfers.c:82:
 	ld	e,(ix+4)
 	ld	d,(ix+5)
 	ld	hl,0x0003
 	add	hl, de
 	ex	(sp), hl
-;source-doc/base-drv/dev_transfers.c:85: done:
+;source-doc/base-drv/dev_transfers.c:84: done:
 	ld	(ix-2),e
 	ld	(ix-1),d
 	pop	bc
@@ -432,12 +432,12 @@ _usbdev_dat_in_trnsfer_0:
 	pop	de
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/dev_transfers.c:87: }
+;source-doc/base-drv/dev_transfers.c:86: }
 	ld	hl,_result
 	ld	a, (hl)
 	sub	0x02
 	jr	NZ,l_usbdev_dat_in_trnsfer_0_00102
-;source-doc/base-drv/dev_transfers.c:88:
+;source-doc/base-drv/dev_transfers.c:87:
 	ex	de, hl
 	inc	hl
 	ld	d, (hl)
@@ -462,18 +462,18 @@ _usbdev_dat_in_trnsfer_0:
 	call	_usbtrn_clear_endpoint_halt
 	pop	af
 	inc	sp
-;source-doc/base-drv/dev_transfers.c:89: usb_error usbdev_dat_in_trnsfer_0(device_config *const device, uint8_t *const buffer, const uint8_t buffer_size) {
+;source-doc/base-drv/dev_transfers.c:88: usb_error usbdev_dat_in_trnsfer_0(device_config *const device, uint8_t *const buffer, const uint8_t buffer_size) {
 	pop	hl
 	push	hl
 	res	0, (hl)
-;source-doc/base-drv/dev_transfers.c:90: endpoint_param *const endpoint = &device->endpoints[0];
+;source-doc/base-drv/dev_transfers.c:89: endpoint_param *const endpoint = &device->endpoints[0];
 	ld	l,0x02
 	jr	l_usbdev_dat_in_trnsfer_0_00103
 l_usbdev_dat_in_trnsfer_0_00102:
-;source-doc/base-drv/dev_transfers.c:93:
+;source-doc/base-drv/dev_transfers.c:92:
 	ld	hl, (_result)
 l_usbdev_dat_in_trnsfer_0_00103:
-;source-doc/base-drv/dev_transfers.c:94: if (result == USB_ERR_STALL) {
+;source-doc/base-drv/dev_transfers.c:93: if (result == USB_ERR_STALL) {
 	ld	sp, ix
 	pop	ix
 	ret
diff --git a/Source/HBIOS/ch376-native/base-drv/enumerate_hub.c.s b/Source/HBIOS/ch376-native/base-drv/enumerate_hub.c.s
index 958d7061..061b599a 100644
--- a/Source/HBIOS/ch376-native/base-drv/enumerate_hub.c.s
+++ b/Source/HBIOS/ch376-native/base-drv/enumerate_hub.c.s
@@ -333,11 +333,9 @@ l_configure_usb_hub_00126:
 	pop	bc
 	or	a
 	jp	NZ, l_configure_usb_hub_00129
-;source-doc/base-drv/enumerate_hub.c:61: if (port_status.wPortStatus.port_connection) {
-	ld	hl,8
-	add	hl, sp
-	ld	a, (hl)
-	and	0x01
+;source-doc/base-drv/enumerate_hub.c:61: if (port_status.wPortStatus & PORT_STAT_CONNECTION) {
+	ld	e,(ix-6)
+	bit	0, e
 	jr	Z,l_configure_usb_hub_00124
 ;source-doc/base-drv/enumerate_hub.c:62: CHECK(hub_clear_feature(hub_config, HUB_FEATURE_PORT_CONNECTION_CHA, i));
 	push	bc
diff --git a/Source/HBIOS/ch376-native/base-drv/transfers.c.s b/Source/HBIOS/ch376-native/base-drv/transfers.c.s
index 47e2cfb1..a7e24d4e 100644
--- a/Source/HBIOS/ch376-native/base-drv/transfers.c.s
+++ b/Source/HBIOS/ch376-native/base-drv/transfers.c.s
@@ -48,7 +48,7 @@ _USB_MODULE_LEDS	.EQU	0xff8a
 ;--------------------------------------------------------
 ; code
 ;--------------------------------------------------------
-;source-doc/base-drv/transfers.c:23:
+;source-doc/base-drv/transfers.c:22:
 ; ---------------------------------
 ; Function usb_ctrl_trnsfer_ext
 ; ---------------------------------
@@ -56,26 +56,26 @@ _usb_ctrl_trnsfer_ext:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/transfers.c:27: const uint8_t             max_packet_size) {
+;source-doc/base-drv/transfers.c:26: const uint8_t             max_packet_size) {
 	ld	a,(ix+5)
 	sub	0x80
 	jr	NC,l_usb_ctrl_trnsfer_ext_00102
-;source-doc/base-drv/transfers.c:28: if ((uint16_t)cmd_packet < LOWER_SAFE_RAM_ADDRESS)
+;source-doc/base-drv/transfers.c:27: if ((uint16_t)cmd_packet < LOWER_SAFE_RAM_ADDRESS)
 	ld	l,0x82
 	jr	l_usb_ctrl_trnsfer_ext_00106
 l_usb_ctrl_trnsfer_ext_00102:
-;source-doc/base-drv/transfers.c:30:
+;source-doc/base-drv/transfers.c:29:
 	ld	a,(ix+7)
 	or	(ix+6)
 	jr	Z,l_usb_ctrl_trnsfer_ext_00104
 	ld	a,(ix+7)
 	sub	0x80
 	jr	NC,l_usb_ctrl_trnsfer_ext_00104
-;source-doc/base-drv/transfers.c:31: if (buffer != 0 && (uint16_t)buffer < LOWER_SAFE_RAM_ADDRESS)
+;source-doc/base-drv/transfers.c:30: if (buffer != 0 && (uint16_t)buffer < LOWER_SAFE_RAM_ADDRESS)
 	ld	l,0x82
 	jr	l_usb_ctrl_trnsfer_ext_00106
 l_usb_ctrl_trnsfer_ext_00104:
-;source-doc/base-drv/transfers.c:33:
+;source-doc/base-drv/transfers.c:32:
 	ld	h,(ix+9)
 	ld	l,(ix+8)
 	push	hl
@@ -90,10 +90,10 @@ l_usb_ctrl_trnsfer_ext_00104:
 	pop	af
 	pop	af
 l_usb_ctrl_trnsfer_ext_00106:
-;source-doc/base-drv/transfers.c:34: return usb_control_transfer(cmd_packet, buffer, device_address, max_packet_size);
+;source-doc/base-drv/transfers.c:33: return usb_control_transfer(cmd_packet, buffer, device_address, max_packet_size);
 	pop	ix
 	ret
-;source-doc/base-drv/transfers.c:38: * @brief Perform a USB control transfer (in or out)
+;source-doc/base-drv/transfers.c:37: * @brief Perform a USB control transfer (in or out)
 ; ---------------------------------
 ; Function usb_control_transfer
 ; ---------------------------------
@@ -103,7 +103,7 @@ _usb_control_transfer:
 	add	ix,sp
 	push	af
 	push	af
-;source-doc/base-drv/transfers.c:43: * @param device_address usb device address
+;source-doc/base-drv/transfers.c:42: * @param device_address usb device address
 	ld	hl,0
 	add	hl, sp
 	set	0, (hl)
@@ -125,30 +125,30 @@ _usb_control_transfer:
 	and	0xfc
 	or	e
 	ld	(hl), a
-;source-doc/base-drv/transfers.c:45: * @return usb_error USB_ERR_OK if all good, otherwise specific error code
+;source-doc/base-drv/transfers.c:44: * @return usb_error USB_ERR_OK if all good, otherwise specific error code
 	ld	c,(ix+4)
 	ld	b,(ix+5)
 	ld	a, (bc)
 	and	0x80
-;source-doc/base-drv/transfers.c:47: usb_error usb_control_transfer(const setup_packet *const cmd_packet,
+;source-doc/base-drv/transfers.c:46: usb_error usb_control_transfer(const setup_packet *const cmd_packet,
 	ld	(ix-1),a
 	or	a
 	jr	Z,l_usb_control_transfer_00102
 	ld	a,(ix+7)
 	or	(ix+6)
 	jr	NZ,l_usb_control_transfer_00102
-;source-doc/base-drv/transfers.c:48: void *const               buffer,
+;source-doc/base-drv/transfers.c:47: void *const               buffer,
 	ld	l,0x0f
 	jp	l_usb_control_transfer_00114
 l_usb_control_transfer_00102:
-;source-doc/base-drv/transfers.c:50: const uint8_t             max_packet_size) {
+;source-doc/base-drv/transfers.c:49: const uint8_t             max_packet_size) {
 	push	bc
 	call	_critical_begin
-;source-doc/base-drv/transfers.c:52: endpoint_param endpoint = {1, 0, max_packet_size};
+;source-doc/base-drv/transfers.c:51: endpoint_param endpoint = {1, 0, max_packet_size};
 	ld	l,(ix+8)
 	call	_ch_set_usb_address
 	pop	bc
-;source-doc/base-drv/transfers.c:54: const uint8_t transferIn = (cmd_packet->bmRequestType & 0x80);
+;source-doc/base-drv/transfers.c:53: const uint8_t transferIn = (cmd_packet->bmRequestType & 0x80);
 	ld	e,(ix+4)
 	ld	d,(ix+5)
 	push	bc
@@ -159,21 +159,21 @@ l_usb_control_transfer_00102:
 	call	_ch_write_data
 	pop	af
 	inc	sp
-;source-doc/base-drv/transfers.c:55:
+;source-doc/base-drv/transfers.c:54:
 	call	_ch_issue_token_setup
-;source-doc/base-drv/transfers.c:56: if (transferIn && buffer == 0)
+;source-doc/base-drv/transfers.c:55: if (transferIn && buffer == 0)
 	call	_ch_short_wait_int_and_get_stat
 	pop	bc
-;source-doc/base-drv/transfers.c:57: return USB_ERR_OTHER;
+;source-doc/base-drv/transfers.c:56: return USB_ERR_OTHER;
 	ld	a, l
 	or	a
 	jr	NZ,l_usb_control_transfer_00113
-;source-doc/base-drv/transfers.c:59: critical_begin();
+;source-doc/base-drv/transfers.c:58: critical_begin();
 	ld	hl,6
 	add	hl, bc
 	ld	c, (hl)
 	inc	hl
-;source-doc/base-drv/transfers.c:62:
+;source-doc/base-drv/transfers.c:61:
 	ld	a,(hl)
 	ld	b,a
 	or	c
@@ -204,58 +204,58 @@ l_usb_control_transfer_00118:
 l_usb_control_transfer_00119:
 	jr	l_usb_control_transfer_00117
 l_usb_control_transfer_00116:
-;source-doc/base-drv/transfers.c:63: ch_write_data((const uint8_t *)cmd_packet, sizeof(setup_packet));
+;source-doc/base-drv/transfers.c:62: ch_write_data((const uint8_t *)cmd_packet, sizeof(setup_packet));
 	ld	l,0x00
 l_usb_control_transfer_00117:
-;source-doc/base-drv/transfers.c:65: result = ch_short_wait_int_and_get_statu();
+;source-doc/base-drv/transfers.c:64: result = ch_short_wait_int_and_get_statu();
 	ld	a, l
 	or	a
 	jr	NZ,l_usb_control_transfer_00113
-;source-doc/base-drv/transfers.c:67:
+;source-doc/base-drv/transfers.c:66:
 	ld	a,(ix-1)
 	or	a
 	jr	Z,l_usb_control_transfer_00112
-;source-doc/base-drv/transfers.c:68: const uint16_t length = cmd_packet->wLength;
+;source-doc/base-drv/transfers.c:67: const uint16_t length = cmd_packet->wLength;
 	ld	l,0x2c
 	call	_ch_command
-;source-doc/base-drv/transfers.c:69:
+;source-doc/base-drv/transfers.c:68:
 	ld	a,0x00
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
-;source-doc/base-drv/transfers.c:70: result = length != 0
+;source-doc/base-drv/transfers.c:69: result = length != 0
 	call	_ch_issue_token_out_ep0
-;source-doc/base-drv/transfers.c:71: ? (transferIn ? ch_data_in_transfer(buffer, length, &endpoint) : ch_data_out_transfer(buffer, length, &endpoint))
+;source-doc/base-drv/transfers.c:70: ? (transferIn ? ch_data_in_transfer(buffer, length, &endpoint) : ch_data_out_transfer(buffer, length, &endpoint))
 	call	_ch_long_wait_int_and_get_statu
-;source-doc/base-drv/transfers.c:73:
+;source-doc/base-drv/transfers.c:72:
 	ld	a,l
 	or	a
 	jr	Z,l_usb_control_transfer_00108
 	sub	0x02
 	jr	NZ,l_usb_control_transfer_00113
 l_usb_control_transfer_00108:
-;source-doc/base-drv/transfers.c:74: CHECK(result)
+;source-doc/base-drv/transfers.c:73: CHECK(result)
 	ld	l,0x00
-;source-doc/base-drv/transfers.c:75:
+;source-doc/base-drv/transfers.c:74:
 	jr	l_usb_control_transfer_00113
-;source-doc/base-drv/transfers.c:78: CH376_DATA_PORT = 0;
+;source-doc/base-drv/transfers.c:77: CH376_DATA_PORT = 0;
 l_usb_control_transfer_00112:
-;source-doc/base-drv/transfers.c:81:
+;source-doc/base-drv/transfers.c:80:
 	call	_ch_issue_token_in_ep0
-;source-doc/base-drv/transfers.c:82: if (result == USB_ERR_OK || result == USB_ERR_STALL) {
+;source-doc/base-drv/transfers.c:81: if (result == USB_ERR_OK || result == USB_ERR_STALL) {
 	call	_ch_long_wait_int_and_get_statu
-;source-doc/base-drv/transfers.c:86:
+;source-doc/base-drv/transfers.c:85:
 l_usb_control_transfer_00113:
-;source-doc/base-drv/transfers.c:87: RETURN_CHECK(result);
+;source-doc/base-drv/transfers.c:86: RETURN_CHECK(result);
 	push	hl
 	call	_critical_end
 	pop	hl
-;source-doc/base-drv/transfers.c:88: }
+;source-doc/base-drv/transfers.c:87: }
 l_usb_control_transfer_00114:
-;source-doc/base-drv/transfers.c:89:
+;source-doc/base-drv/transfers.c:88:
 	ld	sp, ix
 	pop	ix
 	ret
-;source-doc/base-drv/transfers.c:92:
+;source-doc/base-drv/transfers.c:91:
 ; ---------------------------------
 ; Function usb_dat_in_trnsfer_ext
 ; ---------------------------------
@@ -263,26 +263,26 @@ _usb_dat_in_trnsfer_ext:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/transfers.c:93: RETURN_CHECK(result);
+;source-doc/base-drv/transfers.c:92: RETURN_CHECK(result);
 	ld	a,(ix+5)
 	or	(ix+4)
 	jr	Z,l_usb_dat_in_trnsfer_ext_00102
 	ld	a,(ix+5)
 	sub	0x80
 	jr	NC,l_usb_dat_in_trnsfer_ext_00102
-;source-doc/base-drv/transfers.c:94:
+;source-doc/base-drv/transfers.c:93:
 	ld	l,0x82
 	jr	l_usb_dat_in_trnsfer_ext_00106
 l_usb_dat_in_trnsfer_ext_00102:
-;source-doc/base-drv/transfers.c:96: critical_end();
+;source-doc/base-drv/transfers.c:95: critical_end();
 	ld	a,(ix+10)
 	sub	0x80
 	jr	NC,l_usb_dat_in_trnsfer_ext_00105
-;source-doc/base-drv/transfers.c:97: return result;
+;source-doc/base-drv/transfers.c:96: return result;
 	ld	l,0x82
 	jr	l_usb_dat_in_trnsfer_ext_00106
 l_usb_dat_in_trnsfer_ext_00105:
-;source-doc/base-drv/transfers.c:99:
+;source-doc/base-drv/transfers.c:98:
 	ld	l,(ix+9)
 	ld	h,(ix+10)
 	push	hl
@@ -301,67 +301,10 @@ l_usb_dat_in_trnsfer_ext_00105:
 	pop	af
 	inc	sp
 l_usb_dat_in_trnsfer_ext_00106:
-;source-doc/base-drv/transfers.c:100: usb_error
+;source-doc/base-drv/transfers.c:99: usb_error
 	pop	ix
 	ret
-;source-doc/base-drv/transfers.c:103: return USB_BAD_ADDRESS;
-; ---------------------------------
-; Function usb_dat_in_trns_n_ext
-; ---------------------------------
-_usb_dat_in_trns_n_ext:
-	push	ix
-	ld	ix,0
-	add	ix,sp
-;source-doc/base-drv/transfers.c:104:
-	ld	a,(ix+5)
-	or	(ix+4)
-	jr	Z,l_usb_dat_in_trns_n_ext_00102
-	ld	a,(ix+5)
-	and	0xc0
-	jr	NZ,l_usb_dat_in_trns_n_ext_00102
-;source-doc/base-drv/transfers.c:105: if ((uint16_t)endpoint < LOWER_SAFE_RAM_ADDRESS)
-	ld	l,0x82
-	jr	l_usb_dat_in_trns_n_ext_00108
-l_usb_dat_in_trns_n_ext_00102:
-;source-doc/base-drv/transfers.c:107:
-	ld	a,(ix+10)
-	and	0xc0
-	jr	NZ,l_usb_dat_in_trns_n_ext_00105
-;source-doc/base-drv/transfers.c:108: return usb_data_in_transfer(buffer, buffer_size, device_address, endpoint);
-	ld	l,0x82
-	jr	l_usb_dat_in_trns_n_ext_00108
-l_usb_dat_in_trns_n_ext_00105:
-;source-doc/base-drv/transfers.c:110:
-	ld	a,(ix+7)
-	and	0xc0
-	jr	NZ,l_usb_dat_in_trns_n_ext_00107
-;source-doc/base-drv/transfers.c:111: usb_error
-	ld	l,0x82
-	jr	l_usb_dat_in_trns_n_ext_00108
-l_usb_dat_in_trns_n_ext_00107:
-;source-doc/base-drv/transfers.c:113: if (buffer != 0 && ((uint16_t)buffer & 0xC000) == 0)
-	ld	c,(ix+6)
-	ld	b,(ix+7)
-	ld	l,(ix+9)
-	ld	h,(ix+10)
-	push	hl
-	ld	a,(ix+8)
-	push	af
-	inc	sp
-	push	bc
-	ld	l,(ix+4)
-	ld	h,(ix+5)
-	push	hl
-	call	_usb_data_in_transfer_n
-	pop	af
-	pop	af
-	pop	af
-	inc	sp
-l_usb_dat_in_trns_n_ext_00108:
-;source-doc/base-drv/transfers.c:114: return USB_BAD_ADDRESS;
-	pop	ix
-	ret
-;source-doc/base-drv/transfers.c:119: if (((uint16_t)buffer_size & 0xC000) == 0)
+;source-doc/base-drv/transfers.c:104: if ((uint16_t)endpoint < LOWER_SAFE_RAM_ADDRESS)
 ; ---------------------------------
 ; Function usb_data_in_transfer
 ; ---------------------------------
@@ -369,12 +312,12 @@ _usb_data_in_transfer:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/transfers.c:120: return USB_BAD_ADDRESS;
+;source-doc/base-drv/transfers.c:105: return USB_BAD_ADDRESS;
 	call	_critical_begin
-;source-doc/base-drv/transfers.c:122: return usb_data_in_transfer_n(buffer, buffer_size, device_address, endpoint);
+;source-doc/base-drv/transfers.c:107: return usb_data_in_transfer(buffer, buffer_size, device_address, endpoint);
 	ld	l,(ix+8)
 	call	_ch_set_usb_address
-;source-doc/base-drv/transfers.c:124:
+;source-doc/base-drv/transfers.c:109:
 	ld	l,(ix+9)
 	ld	h,(ix+10)
 	push	hl
@@ -390,14 +333,14 @@ _usb_data_in_transfer:
 	pop	af
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/transfers.c:126: * @brief Perform a USB data in on the specififed endpoint
+;source-doc/base-drv/transfers.c:111: * @brief Perform a USB data in on the specififed endpoint
 	call	_critical_end
-;source-doc/base-drv/transfers.c:128: * @param buffer the buffer to receive the data
+;source-doc/base-drv/transfers.c:113: * @param buffer the buffer to receive the data
 	ld	hl, (_result)
-;source-doc/base-drv/transfers.c:129: * @param buffer_size the maximum size of data to be received
+;source-doc/base-drv/transfers.c:114: * @param buffer_size the maximum size of data to be received
 	pop	ix
 	ret
-;source-doc/base-drv/transfers.c:134: usb_error
+;source-doc/base-drv/transfers.c:119: usb_error
 ; ---------------------------------
 ; Function usb_data_in_transfer_n
 ; ---------------------------------
@@ -405,12 +348,12 @@ _usb_data_in_transfer_n:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/transfers.c:135: usb_data_in_transfer(uint8_t *buffer, const uint16_t buffer_size, const uint8_t device_address, endpoint_param *const endpoint) {
+;source-doc/base-drv/transfers.c:120: usb_data_in_transfer(uint8_t *buffer, const uint16_t buffer_size, const uint8_t device_address, endpoint_param *const endpoint) {
 	call	_critical_begin
-;source-doc/base-drv/transfers.c:137:
+;source-doc/base-drv/transfers.c:122:
 	ld	l,(ix+8)
 	call	_ch_set_usb_address
-;source-doc/base-drv/transfers.c:139:
+;source-doc/base-drv/transfers.c:124:
 	ld	l,(ix+9)
 	ld	h,(ix+10)
 	push	hl
@@ -426,14 +369,14 @@ _usb_data_in_transfer_n:
 	pop	af
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/transfers.c:141:
+;source-doc/base-drv/transfers.c:126:
 	call	_critical_end
-;source-doc/base-drv/transfers.c:143:
+;source-doc/base-drv/transfers.c:128:
 	ld	hl, (_result)
-;source-doc/base-drv/transfers.c:144: return result;
+;source-doc/base-drv/transfers.c:129: return result;
 	pop	ix
 	ret
-;source-doc/base-drv/transfers.c:149: *
+;source-doc/base-drv/transfers.c:134: *
 ; ---------------------------------
 ; Function usb_data_out_transfer
 ; ---------------------------------
@@ -441,12 +384,12 @@ _usb_data_out_transfer:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/transfers.c:150: * @param buffer the buffer to receive the data - must be 62 bytes
+;source-doc/base-drv/transfers.c:135: * @param buffer the buffer to receive the data - must be 62 bytes
 	call	_critical_begin
-;source-doc/base-drv/transfers.c:152: * @param device_address the usb address of the device
+;source-doc/base-drv/transfers.c:137: * @param device_address the usb address of the device
 	ld	l,(ix+8)
 	call	_ch_set_usb_address
-;source-doc/base-drv/transfers.c:154: * @return usb_error USB_ERR_OK if all good, otherwise specific error code
+;source-doc/base-drv/transfers.c:139: * @return usb_error USB_ERR_OK if all good, otherwise specific error code
 	ld	l,(ix+9)
 	ld	h,(ix+10)
 	push	hl
@@ -462,10 +405,10 @@ _usb_data_out_transfer:
 	pop	af
 	ld	a, l
 	ld	(_result), a
-;source-doc/base-drv/transfers.c:156: usb_error
+;source-doc/base-drv/transfers.c:141: usb_error
 	call	_critical_end
-;source-doc/base-drv/transfers.c:158: critical_begin();
+;source-doc/base-drv/transfers.c:143: critical_begin();
 	ld	hl, (_result)
-;source-doc/base-drv/transfers.c:159:
+;source-doc/base-drv/transfers.c:144:
 	pop	ix
 	ret
diff --git a/Source/HBIOS/ch376-native/base-drv/usb-base-drv.c.s b/Source/HBIOS/ch376-native/base-drv/usb-base-drv.c.s
index 5ebcdd96..d343f3af 100644
--- a/Source/HBIOS/ch376-native/base-drv/usb-base-drv.c.s
+++ b/Source/HBIOS/ch376-native/base-drv/usb-base-drv.c.s
@@ -68,14 +68,14 @@ _usb_host_bus_reset:
 	call	_ch_cmd_set_usb_mode
 ;source-doc/base-drv/usb-base-drv.c:15: delay_20ms();
 	call	_delay_20ms
-;source-doc/base-drv/ch376.h:111: #endif
+;source-doc/base-drv/ch376.h:111:
 	ld	l,0x0b
 	call	_ch_command
-;source-doc/base-drv/ch376.h:112:
+;source-doc/base-drv/ch376.h:112: #endif
 	ld	a,0x25
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
-;source-doc/base-drv/ch376.h:113: #define calc_max_packet_sizex(packet_size) (packet_size & 0x3FF)
+;source-doc/base-drv/ch376.h:113:
 	ld	a,0xdf
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
@@ -201,7 +201,7 @@ l_usb_init_00112:
 l_usb_init_00113:
 ;source-doc/base-drv/usb-base-drv.c:69: }
 	ret
-;source-doc/base-drv/usb-base-drv.c:71: uint8_t usb_scsi_seek(const uint16_t dev_index, const uint32_t lba) {
+;source-doc/base-drv/usb-base-drv.c:71: usb_error usb_scsi_seek(const uint16_t dev_index, const uint32_t lba) {
 ; ---------------------------------
 ; Function usb_scsi_seek
 ; ---------------------------------
@@ -220,7 +220,7 @@ _usb_scsi_seek:
 	add	hl, sp
 	ld	bc,0x0004
 	ldir
-;source-doc/base-drv/usb-base-drv.c:75: return 0;
+;source-doc/base-drv/usb-base-drv.c:75: return USB_ERR_OK;
 	ld	l,0x00
 ;source-doc/base-drv/usb-base-drv.c:76: }
 	pop	ix
diff --git a/Source/HBIOS/ch376-native/base-drv/usb_state.c.s b/Source/HBIOS/ch376-native/base-drv/usb_state.c.s
index 4fdc511a..12167692 100644
--- a/Source/HBIOS/ch376-native/base-drv/usb_state.c.s
+++ b/Source/HBIOS/ch376-native/base-drv/usb_state.c.s
@@ -187,14 +187,14 @@ l_next_device_config_00102:
 l_next_device_config_00105:
 ;source-doc/base-drv/usb_state.c:72: }
 	ret
-;source-doc/base-drv/usb_state.c:75: device_config *get_usb_device_config(const uint8_t device_index) __sdcccall(1) {
+;source-doc/base-drv/usb_state.c:74: device_config *get_usb_device_config(const uint8_t device_index) __sdcccall(1) {
 ; ---------------------------------
 ; Function get_usb_device_config
 ; ---------------------------------
 _get_usb_device_config:
 	ld	c, a
-;source-doc/base-drv/usb_state.c:76: const _usb_state *const usb_state = get_usb_work_area();
-;source-doc/base-drv/usb_state.c:80: for (device_config *p = first_device_config(usb_state); p; p = next_device_config(usb_state, p)) {
+;source-doc/base-drv/usb_state.c:75: const _usb_state *const usb_state = get_usb_work_area();
+;source-doc/base-drv/usb_state.c:79: for (device_config *p = first_device_config(usb_state); p; p = next_device_config(usb_state, p)) {
 	push	bc
 	ld	hl,_x
 	call	_first_device_config
@@ -204,33 +204,33 @@ l_get_usb_device_config_00107:
 	ld	a, d
 	or	e
 	jr	Z,l_get_usb_device_config_00105
-;source-doc/base-drv/usb_state.c:81: if (p->type != USB_NOT_SUPPORTED) {
+;source-doc/base-drv/usb_state.c:80: if (p->type != USB_NOT_SUPPORTED) {
 	ld	l, e
 	ld	h, d
 	ld	a, (hl)
 	and	0x0f
 	jr	Z,l_get_usb_device_config_00108
-;source-doc/base-drv/usb_state.c:82: if (counter == device_index)
+;source-doc/base-drv/usb_state.c:81: if (counter == device_index)
 	ld	a, c
 	sub	b
-;source-doc/base-drv/usb_state.c:83: return p;
+;source-doc/base-drv/usb_state.c:82: return p;
 	jr	Z,l_get_usb_device_config_00109
-;source-doc/base-drv/usb_state.c:84: counter++;
+;source-doc/base-drv/usb_state.c:83: counter++;
 	inc	b
 l_get_usb_device_config_00108:
-;source-doc/base-drv/usb_state.c:80: for (device_config *p = first_device_config(usb_state); p; p = next_device_config(usb_state, p)) {
+;source-doc/base-drv/usb_state.c:79: for (device_config *p = first_device_config(usb_state); p; p = next_device_config(usb_state, p)) {
 	push	bc
 	ld	hl,_x
 	call	_next_device_config
 	pop	bc
 	jr	l_get_usb_device_config_00107
 l_get_usb_device_config_00105:
-;source-doc/base-drv/usb_state.c:88: return NULL; // is not a usb device
+;source-doc/base-drv/usb_state.c:87: return NULL; // is not a usb device
 	ld	de,0x0000
 l_get_usb_device_config_00109:
-;source-doc/base-drv/usb_state.c:89: }
+;source-doc/base-drv/usb_state.c:88: }
 	ret
-;source-doc/base-drv/usb_state.c:91: usb_device_type get_usb_device_type(const uint8_t dev_index) {
+;source-doc/base-drv/usb_state.c:90: usb_device_type get_usb_device_type(const uint8_t dev_index) {
 ; ---------------------------------
 ; Function get_usb_device_type
 ; ---------------------------------
@@ -238,24 +238,24 @@ _get_usb_device_type:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/base-drv/usb_state.c:92: const device_config *dev = get_usb_device_config(dev_index);
+;source-doc/base-drv/usb_state.c:91: const device_config *dev = get_usb_device_config(dev_index);
 	ld	a,(ix+4)
 	call	_get_usb_device_config
 	ld	l, e
-;source-doc/base-drv/usb_state.c:94: if (dev == NULL)
+;source-doc/base-drv/usb_state.c:93: if (dev == NULL)
 	ld	a,d
 	ld	h,a
 	or	e
 	jr	NZ,l_get_usb_device_type_00102
-;source-doc/base-drv/usb_state.c:95: return -1;
+;source-doc/base-drv/usb_state.c:94: return -1;
 	ld	l,0xff
 	jr	l_get_usb_device_type_00103
 l_get_usb_device_type_00102:
-;source-doc/base-drv/usb_state.c:97: return dev->type;
+;source-doc/base-drv/usb_state.c:96: return dev->type;
 	ld	a, (hl)
 	and	0x0f
 	ld	l, a
 l_get_usb_device_type_00103:
-;source-doc/base-drv/usb_state.c:98: }
+;source-doc/base-drv/usb_state.c:97: }
 	pop	ix
 	ret
diff --git a/Source/HBIOS/ch376-native/keyboard/kyb_driver.c.s b/Source/HBIOS/ch376-native/keyboard/kyb_driver.c.s
index 0ede7fe4..f262150b 100644
--- a/Source/HBIOS/ch376-native/keyboard/kyb_driver.c.s
+++ b/Source/HBIOS/ch376-native/keyboard/kyb_driver.c.s
@@ -358,14 +358,14 @@ _usb_kyb_tick:
 	or	a
 ;source-doc/keyboard/kyb_driver.c:120: if (is_in_critical_section())
 	jr	NZ,l_usb_kyb_tick_00112
-;././source-doc/base-drv//ch376.h:111: #endif
+;././source-doc/base-drv//ch376.h:111:
 	ld	l,0x0b
 	call	_ch_command
-;././source-doc/base-drv//ch376.h:112:
+;././source-doc/base-drv//ch376.h:112: #endif
 	ld	a,0x25
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
-;././source-doc/base-drv//ch376.h:113: #define calc_max_packet_sizex(packet_size) (packet_size & 0x3FF)
+;././source-doc/base-drv//ch376.h:113:
 	ld	a,0x1f
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
@@ -383,14 +383,14 @@ _usb_kyb_tick:
 	inc	sp
 	ld	a, l
 	ld	(_result), a
-;././source-doc/base-drv//ch376.h:111: #endif
+;././source-doc/base-drv//ch376.h:111:
 	ld	l,0x0b
 	call	_ch_command
-;././source-doc/base-drv//ch376.h:112:
+;././source-doc/base-drv//ch376.h:112: #endif
 	ld	a,0x25
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
-;././source-doc/base-drv//ch376.h:113: #define calc_max_packet_sizex(packet_size) (packet_size & 0x3FF)
+;././source-doc/base-drv//ch376.h:113:
 	ld	a,0xdf
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.c b/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.c
index 376a5ef2..bf825ee3 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.c
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.c
@@ -109,7 +109,7 @@ uint8_t ch_probe(void) {
   return false;
 }
 
-uint8_t ch_cmd_set_usb_mode(const uint8_t mode) __z88dk_fastcall {
+usb_error ch_cmd_set_usb_mode(const uint8_t mode) __z88dk_fastcall {
   uint8_t result = 0;
 
   CH376_COMMAND_PORT = CH_CMD_SET_USB_MODE;
@@ -187,7 +187,7 @@ done:
 }
 
 // TODO: review: does buffer_size need to be signed?
-usb_error ch_data_in_transfer_n(uint8_t *const buffer, int8_t *const buffer_size, endpoint_param *const endpoint) {
+usb_error ch_data_in_transfer_n(uint8_t *const buffer, uint8_t *const buffer_size, endpoint_param *const endpoint) {
   uint8_t   count;
   usb_error result;
 
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.h b/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.h
index 381e84e1..f9240966 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.h
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/ch376.h
@@ -4,6 +4,7 @@
 
 #include "ch376inc.h"
 #include "delay.h"
+#include <stdint.h>
 #include <stdlib.h>
 
 typedef enum {
@@ -157,7 +158,7 @@ extern usb_error ch_control_transfer_request_descriptor(const uint8_t descriptor
 extern usb_error ch_control_transfer_set_address(const uint8_t device_address) __z88dk_fastcall;
 extern usb_error ch_control_transfer_set_config(const uint8_t config_value) __z88dk_fastcall;
 extern usb_error ch_data_in_transfer(uint8_t *buffer, int16_t data_length, endpoint_param *const endpoint);
-extern usb_error ch_data_in_transfer_n(uint8_t *buffer, int8_t *const buffer_size, endpoint_param *const endpoint);
+extern usb_error ch_data_in_transfer_n(uint8_t *buffer, uint8_t *const buffer_size, endpoint_param *const endpoint);
 extern usb_error ch_data_out_transfer(const uint8_t *buffer, int16_t buffer_length, endpoint_param *const endpoint);
 
 inline void ch_configure_nak_retry(const ch_nak_retry_type retry, const uint8_t number_of_retries) {
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/class_hub.h b/Source/HBIOS/ch376-native/source-doc/base-drv/class_hub.h
index 7d7c75da..73d05184 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/class_hub.h
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/class_hub.h
@@ -36,40 +36,27 @@ typedef struct {
 } hub_descriptor;
 
 typedef struct {
-  union {
-    struct {
-      uint8_t port_connection : 1;
-      uint8_t port_enable : 1;
-      uint8_t port_suspend : 1;
-      uint8_t port_over_current : 1;
-      uint8_t port_reset : 1;
-      uint8_t reserved : 3;
-      uint8_t port_power : 1;
-      uint8_t port_low_speed : 1;
-      uint8_t port_high_speed : 1;
-      uint8_t port_test : 1;
-      uint8_t port_indicator : 1;
-    };
-
-    uint16_t val;
-
-  } wPortStatus;
-
-  union {
-    struct {
-      uint8_t c_port_connection : 1;
-      uint8_t c_port_enable : 1;
-      uint8_t c_port_suspend : 1;
-      uint8_t c_port_over_current : 1;
-      uint8_t c_port_reset : 1;
-    };
-
-    uint16_t val;
-
-  } wPortChange;
-
+  uint16_t wPortStatus;
+  uint16_t wPortChange;
 } hub_port_status;
 
+#define PORT_STAT_CONNECTION  0x0001
+#define PORT_STAT_ENABLE      0x0002
+#define PORT_STAT_SUSPEND     0x0004
+#define PORT_STAT_OVERCURRENT 0x0008
+#define PORT_STAT_RESET       0x0010
+#define PORT_STAT_POWER       0x0100
+#define PORT_STAT_LOW_SPEED   0x0200
+#define PORT_STAT_HIGH_SPEED  0x0400
+#define PORT_STAT_TEST        0x0800
+#define PORT_STAT_INDICATOR   0x1000
+
+#define PORT_STAT_C_CONNECTION  0x0001
+#define PORT_STAT_C_ENABLE      0x0002
+#define PORT_STAT_C_SUSPEND     0x0004
+#define PORT_STAT_C_OVERCURRENT 0x0008
+#define PORT_STAT_C_RESET       0x0010
+
 usb_error hub_get_descriptor(const device_config_hub *const hub_config, hub_descriptor *const hub_description) __sdcccall(1);
 
 #endif
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/dev_transfers.c b/Source/HBIOS/ch376-native/source-doc/base-drv/dev_transfers.c
index 9abc2988..99e08a5a 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/dev_transfers.c
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/dev_transfers.c
@@ -12,13 +12,12 @@
 
 #include "dev_transfers.h"
 #include "ch376.h"
+#include "critical-section.h"
 #include "delay.h"
+#include "ez80-helpers.h"
 #include "protocol.h"
 #include <stdlib.h>
 
-#include <critical-section.h>
-
-#include "ez80-helpers.h"
 /**
  * @brief Perform a USB control transfer (in or out)
  * See https://www.beyondlogic.org/usbnutshell/usb4.shtml for a description of the USB control transfer
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_hub.c b/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_hub.c
index d838c452..1db8ddb2 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_hub.c
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_hub.c
@@ -58,7 +58,7 @@ usb_error configure_usb_hub(_working *const working) __z88dk_fastcall {
 
     CHECK(hub_get_status_port(hub_config, i, &port_status));
 
-    if (port_status.wPortStatus.port_connection) {
+    if (port_status.wPortStatus & PORT_STAT_CONNECTION) {
       CHECK(hub_clear_feature(hub_config, HUB_FEATURE_PORT_CONNECTION_CHANGE, i));
 
       CHECK(hub_clear_feature(hub_config, FEAT_PORT_ENABLE_CHANGE, i));
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_storage.h b/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_storage.h
index 849fa3a4..17f81a8a 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_storage.h
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/enumerate_storage.h
@@ -1,6 +1,7 @@
 #ifndef __USB_ENUMERATE_STORAGE
 #define __USB_ENUMERATE_STORAGE
 
+#include "dev_transfers.h"
 #include "protocol.h"
 
 extern void parse_endpoints(device_config_storage *const storage_dev, const endpoint_descriptor const *pEndpoint);
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/print.h b/Source/HBIOS/ch376-native/source-doc/base-drv/print.h
index 480f73f7..df7491b3 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/print.h
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/print.h
@@ -1,6 +1,7 @@
 #ifndef __XPRINT
 #define __XPRINT
 
+#include <stdint.h>
 #include <stdlib.h>
 
 extern void print_hex(const char c) __z88dk_fastcall;
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/transfers.c b/Source/HBIOS/ch376-native/source-doc/base-drv/transfers.c
index 2aab410e..5e35afee 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/transfers.c
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/transfers.c
@@ -12,11 +12,10 @@
 
 #include "transfers.h"
 #include "ch376.h"
+#include "critical-section.h"
 #include "delay.h"
 #include "ez80-helpers.h"
 #include "print.h"
-#include "z80.h"
-#include <critical-section.h>
 #include <stdlib.h>
 
 #define LOWER_SAFE_RAM_ADDRESS 0x8000
@@ -108,20 +107,6 @@ usb_dat_in_trnsfer_ext(uint8_t *buffer, const uint16_t buffer_size, const uint8_
   return usb_data_in_transfer(buffer, buffer_size, device_address, endpoint);
 }
 
-usb_error
-usb_dat_in_trns_n_ext(uint8_t *buffer, uint16_t *buffer_size, const uint8_t device_address, endpoint_param *const endpoint) {
-  if (buffer != 0 && ((uint16_t)buffer & 0xC000) == 0)
-    return USB_BAD_ADDRESS;
-
-  if (((uint16_t)endpoint & 0xC000) == 0)
-    return USB_BAD_ADDRESS;
-
-  if (((uint16_t)buffer_size & 0xC000) == 0)
-    return USB_BAD_ADDRESS;
-
-  return usb_data_in_transfer_n(buffer, buffer_size, device_address, endpoint);
-}
-
 /**
  * @brief Perform a USB data in on the specififed endpoint
  *
@@ -145,7 +130,7 @@ usb_data_in_transfer(uint8_t *buffer, const uint16_t buffer_size, const uint8_t
 }
 
 /**
- * @brief Perform a USB data in on the specififed endpoint
+ * @brief Perform a USB data in on the specified endpoint
  *
  * @param buffer the buffer to receive the data - must be 62 bytes
  * @param buffer_size  on exit the actual size of data received
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.c b/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.c
index fb29c190..b809de1d 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.c
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.c
@@ -68,9 +68,9 @@ uint16_t usb_init(uint8_t state) __z88dk_fastcall {
   return (uint16_t)count_of_devices() << 8 | 4;
 }
 
-uint8_t usb_scsi_seek(const uint16_t dev_index, const uint32_t lba) {
+usb_error usb_scsi_seek(const uint16_t dev_index, const uint32_t lba) {
   device_config_storage *const dev = (device_config_storage *)get_usb_device_config(dev_index);
 
   dev->current_lba = lba;
-  return 0;
+  return USB_ERR_OK;
 }
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.h b/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.h
index 249e894b..a2ab3b1a 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.h
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/usb-base-drv.h
@@ -1,8 +1,8 @@
 #ifndef __USB_BASE_DRV
 #define __USB_BASE_DRV
 
+#include "dev_transfers.h"
 #include "usb_state.h"
-#include <dev_transfers.h>
 #include <stdint.h>
 
 extern uint16_t usb_init(uint8_t state) __z88dk_fastcall;
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/usb_state.c b/Source/HBIOS/ch376-native/source-doc/base-drv/usb_state.c
index cb16cd19..0824b4ef 100644
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/usb_state.c
+++ b/Source/HBIOS/ch376-native/source-doc/base-drv/usb_state.c
@@ -71,7 +71,6 @@ device_config *next_device_config(const _usb_state *const usb_state, const devic
   return result;
 }
 
-// always usb work area
 device_config *get_usb_device_config(const uint8_t device_index) __sdcccall(1) {
   const _usb_state *const usb_state = get_usb_work_area();
 
diff --git a/Source/HBIOS/ch376-native/source-doc/base-drv/z80.h b/Source/HBIOS/ch376-native/source-doc/base-drv/z80.h
deleted file mode 100644
index a086bfeb..00000000
--- a/Source/HBIOS/ch376-native/source-doc/base-drv/z80.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef __Z80_HELPERS
-#define __Z80_HELPERS
-
-#include <stdint.h>
-
-#endif