diff --git a/bootloader/usb.c b/bootloader/usb.c
index 0f17df6a0c..48e6692a71 100644
--- a/bootloader/usb.c
+++ b/bootloader/usb.c
@@ -34,6 +34,9 @@
 #include "signatures.h"
 #include "sha2.h"
 
+#define ENDPOINT_ADDRESS_IN         (0x81)
+#define ENDPOINT_ADDRESS_OUT        (0x01)
+
 static const struct usb_device_descriptor dev_descr = {
 	.bLength = USB_DT_DEVICE_SIZE,
 	.bDescriptorType = USB_DT_DEVICE,
@@ -51,66 +54,20 @@ static const struct usb_device_descriptor dev_descr = {
 	.bNumConfigurations = 1,
 };
 
-/* got via usbhid-dump from CP2110 */
 static const uint8_t hid_report_descriptor[] = {
-	0x06, 0x00, 0xFF, 0x09, 0x01, 0xA1, 0x01, 0x09, 0x01, 0x75, 0x08, 0x95, 0x40, 0x26, 0xFF, 0x00,
-	0x15, 0x00, 0x85, 0x01, 0x95, 0x01, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x02,
-	0x95, 0x02, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x03, 0x95, 0x03, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x04, 0x95, 0x04, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x05, 0x95, 0x05, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x06,
-	0x95, 0x06, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x07, 0x95, 0x07, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x08, 0x95, 0x08, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x09, 0x95, 0x09, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x0A,
-	0x95, 0x0A, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x0B, 0x95, 0x0B, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x0C, 0x95, 0x0C, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x0D, 0x95, 0x0D, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x0E,
-	0x95, 0x0E, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x0F, 0x95, 0x0F, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x10, 0x95, 0x10, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x11, 0x95, 0x11, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x12,
-	0x95, 0x12, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x13, 0x95, 0x13, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x14, 0x95, 0x14, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x15, 0x95, 0x15, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x16,
-	0x95, 0x16, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x17, 0x95, 0x17, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x18, 0x95, 0x18, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x19, 0x95, 0x19, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x1A,
-	0x95, 0x1A, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x1B, 0x95, 0x1B, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x1C, 0x95, 0x1C, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x1D, 0x95, 0x1D, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x1E,
-	0x95, 0x1E, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x1F, 0x95, 0x1F, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x20, 0x95, 0x20, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x21, 0x95, 0x21, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x22,
-	0x95, 0x22, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x23, 0x95, 0x23, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x24, 0x95, 0x24, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x25, 0x95, 0x25, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x26,
-	0x95, 0x26, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x27, 0x95, 0x27, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x28, 0x95, 0x28, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x29, 0x95, 0x29, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x2A,
-	0x95, 0x2A, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x2B, 0x95, 0x2B, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x2C, 0x95, 0x2C, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x2D, 0x95, 0x2D, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x2E,
-	0x95, 0x2E, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x2F, 0x95, 0x2F, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x30, 0x95, 0x30, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x31, 0x95, 0x31, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x32,
-	0x95, 0x32, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x33, 0x95, 0x33, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x34, 0x95, 0x34, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x35, 0x95, 0x35, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x36,
-	0x95, 0x36, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x37, 0x95, 0x37, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x38, 0x95, 0x38, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x39, 0x95, 0x39, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x3A,
-	0x95, 0x3A, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x3B, 0x95, 0x3B, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x3C, 0x95, 0x3C, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01,
-	0x91, 0x02, 0x85, 0x3D, 0x95, 0x3D, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x3E,
-	0x95, 0x3E, 0x09, 0x01, 0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x3F, 0x95, 0x3F, 0x09, 0x01,
-	0x81, 0x02, 0x09, 0x01, 0x91, 0x02, 0x85, 0x40, 0x95, 0x01, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x41,
-	0x95, 0x01, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x42, 0x95, 0x06, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x43,
-	0x95, 0x01, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x44, 0x95, 0x02, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x45,
-	0x95, 0x04, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x46, 0x95, 0x02, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x47,
-	0x95, 0x02, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x50, 0x95, 0x08, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x51,
-	0x95, 0x01, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x52, 0x95, 0x01, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x60,
-	0x95, 0x0A, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x61, 0x95, 0x3F, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x62,
-	0x95, 0x3F, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x63, 0x95, 0x3F, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x64,
-	0x95, 0x3F, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x65, 0x95, 0x3E, 0x09, 0x01, 0xB1, 0x02, 0x85, 0x66,
-	0x95, 0x13, 0x09, 0x01, 0xB1, 0x02, 0xC0,
+	0x06, 0x00, 0xff,  // USAGE_PAGE (Reserved)
+	0x09, 0x01,        // USAGE (1)
+	0xa1, 0x01,        // COLLECTION (Application)
+	0x15, 0x00,        // LOGICAL_MINIMUM (0)
+	0x26, 0xff, 0x00,  // LOGICAL_MAXIMUM (255)
+	0x85, 0x3f,        // REPORT_ID (63)
+	0x75, 0x08,        // REPORT_SIZE (8)
+	0x95, 0x3f,        // REPORT_COUNT (63)
+	0x09, 0x01,        // USAGE (1)
+	0x81, 0x02,        // INPUT (Data,Var,Abs)
+	0x09, 0x01,        // USAGE (1)
+	0x91, 0x02,        // OUTPUT (Data,Var,Abs)
+	0xc0               // END_COLLECTION
 };
 
 static const struct {
@@ -136,14 +93,14 @@ static const struct {
 static const struct usb_endpoint_descriptor hid_endpoints[2] = {{
 	.bLength = USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType = USB_DT_ENDPOINT,
-	.bEndpointAddress = 0x81,
+	.bEndpointAddress = ENDPOINT_ADDRESS_IN,
 	.bmAttributes = USB_ENDPOINT_ATTR_INTERRUPT,
 	.wMaxPacketSize = 64,
 	.bInterval = 1,
 }, {
 	.bLength = USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType = USB_DT_ENDPOINT,
-	.bEndpointAddress = 0x02,
+	.bEndpointAddress = ENDPOINT_ADDRESS_OUT,
 	.bmAttributes = USB_ENDPOINT_ATTR_INTERRUPT,
 	.wMaxPacketSize = 64,
 	.bInterval = 1,
@@ -194,8 +151,10 @@ static int hid_control_request(usbd_device *dev, struct usb_setup_data *req, uin
 
 	if ((req->bmRequestType != 0x81) ||
 	    (req->bRequest != USB_REQ_GET_DESCRIPTOR) ||
-	    (req->wValue != 0x2200)) return 0;
+	    (req->wValue != 0x2200))
+		return 0;
 
+	/* Handle the HID report descriptor. */
 	*buf = (uint8_t *)hid_report_descriptor;
 	*len = sizeof(hid_report_descriptor);
 
@@ -222,7 +181,7 @@ static uint8_t meta_backup[FLASH_META_LEN];
 static void send_msg_success(usbd_device *dev)
 {
 	// send response: Success message (id 2), payload len 0
-	while ( usbd_ep_write_packet(dev, 0x81,
+	while ( usbd_ep_write_packet(dev, ENDPOINT_ADDRESS_IN,
 		"?##"				// header
 		"\x00\x02"			// msg_id
 		"\x00\x00\x00\x00"	// payload_len
@@ -234,7 +193,7 @@ static void send_msg_failure(usbd_device *dev)
 {
 	// send response: Failure message (id 3), payload len 2
 		// code = 99 (Failure_FirmwareError)
-	while ( usbd_ep_write_packet(dev, 0x81,
+	while ( usbd_ep_write_packet(dev, ENDPOINT_ADDRESS_IN,
 		"?##"				// header
 		"\x00\x03"			// msg_id
 		"\x00\x00\x00\x02"	// payload_len
@@ -251,7 +210,7 @@ static void send_msg_features(usbd_device *dev)
 		// minor_version = VERSION_MINOR
 		// patch_version = VERSION_PATCH
 		// bootloader_mode = True
-	while ( usbd_ep_write_packet(dev, 0x81,
+	while ( usbd_ep_write_packet(dev, ENDPOINT_ADDRESS_IN,
 		"?##"				// header
 		"\x00\x11"			// msg_id
 		"\x00\x00\x00\x1b"	// payload_len
@@ -264,7 +223,7 @@ static void send_msg_buttonrequest_firmwarecheck(usbd_device *dev)
 {
 	// send response: ButtonRequest message (id 26), payload len 2
 		// code = ButtonRequest_FirmwareCheck (9)
-	while ( usbd_ep_write_packet(dev, 0x81,
+	while ( usbd_ep_write_packet(dev, ENDPOINT_ADDRESS_IN,
 		"?##"				// header
 		"\x00\x1a"			// msg_id
 		"\x00\x00\x00\x02"	// payload_len
@@ -284,7 +243,7 @@ static void hid_rx_callback(usbd_device *dev, uint8_t ep)
 	uint32_t *w;
 	static SHA256_CTX ctx;
 
-	if ( usbd_ep_read_packet(dev, 0x02, buf, 64) != 64) return;
+	if ( usbd_ep_read_packet(dev, ENDPOINT_ADDRESS_OUT, buf, 64) != 64) return;
 
 	if (flash_state == STATE_END) {
 		return;
@@ -485,8 +444,8 @@ static void hid_set_config(usbd_device *dev, uint16_t wValue)
 {
 	(void)wValue;
 
-	usbd_ep_setup(dev, 0x81, USB_ENDPOINT_ATTR_INTERRUPT, 64, 0);
-	usbd_ep_setup(dev, 0x02, USB_ENDPOINT_ATTR_INTERRUPT, 64, hid_rx_callback);
+	usbd_ep_setup(dev, ENDPOINT_ADDRESS_IN, USB_ENDPOINT_ATTR_INTERRUPT, 64, 0);
+	usbd_ep_setup(dev, ENDPOINT_ADDRESS_OUT, USB_ENDPOINT_ATTR_INTERRUPT, 64, hid_rx_callback);
 
 	usbd_register_control_callback(
 		dev,