diff --git a/src/main.c b/src/main.c
index 21439a1..44204c7 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2,6 +2,7 @@
  * The MIT License (MIT)
  *
  * Copyright (c) 2021 Raspberry Pi (Trading) Ltd.
+ * Copyright (c) 2021 Peter Lawrence
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -35,17 +36,27 @@
 #include "cdc_uart.h"
 #include "get_serial.h"
 #include "led.h"
+#include "DAP.h"
 
 // UART0 for Picoprobe debug
 // UART1 for picoprobe to target device
 
+static uint8_t TxDataBuffer[CFG_TUD_HID_EP_BUFSIZE];
+static uint8_t RxDataBuffer[CFG_TUD_HID_EP_BUFSIZE];
+
+void dap_task(void);
+
 int main(void) {
 
     board_init();
     usb_serial_init();
     cdc_uart_init();
     tusb_init();
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_OPENOCD_CUSTOM)
     probe_init();
+#else
+    DAP_Setup();
+#endif
     led_init();
 
     picoprobe_info("Welcome to Picoprobe!\n");
@@ -53,9 +64,87 @@ int main(void) {
     while (1) {
         tud_task(); // tinyusb device task
         cdc_task();
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_OPENOCD_CUSTOM)
         probe_task();
         led_task();
+#elif (PICOPROBE_DEBUG_PROTOCOL == PROTO_DAP_V2)
+        dap_task();
+#endif
     }
 
     return 0;
-}
\ No newline at end of file
+}
+
+void dap_task(void)
+{
+  uint32_t count;
+  uint32_t resp_len;
+  if (tud_vendor_available()) {
+     count = tud_vendor_read(RxDataBuffer, sizeof(RxDataBuffer));
+     resp_len = DAP_ProcessCommand(RxDataBuffer, TxDataBuffer);
+     tud_vendor_write(TxDataBuffer, resp_len);
+  }
+}
+
+uint16_t tud_hid_get_report_cb(uint8_t itf, uint8_t report_id, hid_report_type_t report_type, uint8_t* buffer, uint16_t reqlen)
+{
+  // TODO not Implemented
+  (void) itf;
+  (void) report_id;
+  (void) report_type;
+  (void) buffer;
+  (void) reqlen;
+
+  return 0;
+}
+
+void tud_hid_set_report_cb(uint8_t itf, uint8_t report_id, hid_report_type_t report_type, uint8_t const* RxDataBuffer, uint16_t bufsize)
+{
+  uint32_t response_size = TU_MIN(CFG_TUD_HID_EP_BUFSIZE, bufsize);
+
+  // This doesn't use multiple report and report ID
+  (void) itf;
+  (void) report_id;
+  (void) report_type;
+
+  DAP_ProcessCommand(RxDataBuffer, TxDataBuffer);
+
+  tud_hid_report(0, TxDataBuffer, response_size);
+}
+
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_DAP_V2)
+extern uint8_t const desc_ms_os_20[];
+
+bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const * request)
+{
+  // nothing to with DATA & ACK stage
+  if (stage != CONTROL_STAGE_SETUP) return true;
+
+  switch (request->bmRequestType_bit.type)
+  {
+    case TUSB_REQ_TYPE_VENDOR:
+      switch (request->bRequest)
+      {
+        case 1:
+          if ( request->wIndex == 7 )
+          {
+            // Get Microsoft OS 2.0 compatible descriptor
+            uint16_t total_len;
+            memcpy(&total_len, desc_ms_os_20+8, 2);
+
+            return tud_control_xfer(rhport, request, (void*) desc_ms_os_20, total_len);
+          }else
+          {
+            return false;
+          }
+
+        default: break;
+      }
+    break;
+    default: break;
+  }
+
+  // stall unknown request
+  return false;
+}
+#endif
diff --git a/src/picoprobe_config.h b/src/picoprobe_config.h
index 87be47b..4bca6c5 100644
--- a/src/picoprobe_config.h
+++ b/src/picoprobe_config.h
@@ -72,6 +72,15 @@
 #define PICOPROBE_LED PICO_DEFAULT_LED_PIN
 #endif
 
+#define PROTO_OPENOCD_CUSTOM 0
+#define PROTO_DAP_V1 1
+#define PROTO_DAP_V2 2
+
+// Interface config
+#ifndef PICOPROBE_DEBUG_PROTOCOL
+#define PICOPROBE_DEBUG_PROTOCOL PROTO_OPENOCD_CUSTOM
+#endif
+
 #endif
 
 #endif
diff --git a/src/tusb_config.h b/src/tusb_config.h
index b4dc45c..ad0e1fa 100644
--- a/src/tusb_config.h
+++ b/src/tusb_config.h
@@ -62,7 +62,7 @@
 #endif
 
 //------------- CLASS -------------//
-#define CFG_TUD_HID             0
+#define CFG_TUD_HID             1
 #define CFG_TUD_CDC             1
 #define CFG_TUD_MSC             0
 #define CFG_TUD_MIDI            0
diff --git a/src/usb_descriptors.c b/src/usb_descriptors.c
index dd6b4f0..49a783e 100644
--- a/src/usb_descriptors.c
+++ b/src/usb_descriptors.c
@@ -2,6 +2,8 @@
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ * Copyright (c) 2021 Peter Lawrence
+ * Copyright (c) 2022 Raspberry Pi Ltd
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -25,7 +27,7 @@
 
 #include "tusb.h"
 #include "get_serial.h"
-
+#include "picoprobe_config.h"
 
 //--------------------------------------------------------------------+
 // Device Descriptors
@@ -34,14 +36,22 @@ tusb_desc_device_t const desc_device =
 {
     .bLength            = sizeof(tusb_desc_device_t),
     .bDescriptorType    = TUSB_DESC_DEVICE,
-    .bcdUSB             = 0x0110, // // USB Specification version 1.1
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_DAP_V2)
+    .bcdUSB             = 0x0210, // USB Specification version 2.1 for BOS
+#else
+    .bcdUSB             = 0x0110,
+#endif
     .bDeviceClass       = 0x00, // Each interface specifies its own
     .bDeviceSubClass    = 0x00, // Each interface specifies its own
     .bDeviceProtocol    = 0x00,
     .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
 
     .idVendor           = 0x2E8A, // Pi
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_OPENOCD_CUSTOM)
     .idProduct          = 0x0004, // Picoprobe
+#else
+    .idProduct          = 0x000c, // CMSIS-DAP adapter
+#endif
     .bcdDevice          = 0x0100, // Version 01.00
     .iManufacturer      = 0x01,
     .iProduct           = 0x02,
@@ -62,9 +72,9 @@ uint8_t const * tud_descriptor_device_cb(void)
 
 enum
 {
+  ITF_NUM_PROBE, // Old versions of Keil MDK only look at interface 0
   ITF_NUM_CDC_COM,
   ITF_NUM_CDC_DATA,
-  ITF_NUM_PROBE,
   ITF_NUM_TOTAL
 };
 
@@ -74,18 +84,39 @@ enum
 #define PROBE_OUT_EP_NUM 0x04
 #define PROBE_IN_EP_NUM 0x85
 
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_DAP_V1)
+#define CONFIG_TOTAL_LEN  (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN + TUD_HID_INOUT_DESC_LEN)
+#else
 #define CONFIG_TOTAL_LEN  (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN + TUD_VENDOR_DESC_LEN)
+#endif
+
+static uint8_t const desc_hid_report[] =
+{
+  TUD_HID_REPORT_DESC_GENERIC_INOUT(CFG_TUD_HID_EP_BUFSIZE)
+};
+
+uint8_t const * tud_hid_descriptor_report_cb(uint8_t itf)
+{
+  (void) itf;
+  return desc_hid_report;
+}
 
 uint8_t const desc_configuration[] =
 {
   TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, 100),
-
-  // Interface 0 + 1
-  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_COM, 0, CDC_NOTIFICATION_EP_NUM, 64, CDC_DATA_OUT_EP_NUM, CDC_DATA_IN_EP_NUM, 64),
-
-  // Interface 2
-  TUD_VENDOR_DESCRIPTOR(ITF_NUM_PROBE, 0, PROBE_OUT_EP_NUM, PROBE_IN_EP_NUM, 64)
-
+  // Interface 0
+#if (PICOPROBE_DEBUG_PROTOCOL == PROTO_DAP_V1)
+  // HID (named interface)
+  TUD_HID_INOUT_DESCRIPTOR(ITF_NUM_PROBE, 4, HID_ITF_PROTOCOL_NONE, sizeof(desc_hid_report), PROBE_OUT_EP_NUM, PROBE_IN_EP_NUM, CFG_TUD_HID_EP_BUFSIZE, 1),
+#elif (PICOPROBE_DEBUG_PROTOCOL == PROTO_DAP_V2)
+  // Bulk (named interface)
+  TUD_VENDOR_DESCRIPTOR(ITF_NUM_PROBE, 5, PROBE_OUT_EP_NUM, PROBE_IN_EP_NUM, 64),
+#elif (PICOPROBE_DEBUG_PROTOCOL == PROTO_OPENOCD_CUSTOM)
+  // Bulk
+  TUD_VENDOR_DESCRIPTOR(ITF_NUM_PROBE, 0, PROBE_OUT_EP_NUM, PROBE_IN_EP_NUM, 64),
+#endif
+  // Interface 1 + 2
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_COM, 6, CDC_NOTIFICATION_EP_NUM, 64, CDC_DATA_OUT_EP_NUM, CDC_DATA_IN_EP_NUM, 64),
 };
 
 // Invoked when received GET CONFIGURATION DESCRIPTOR
@@ -108,6 +139,9 @@ char const* string_desc_arr [] =
   "Raspberry Pi", // 1: Manufacturer
   "Picoprobe",    // 2: Product
   usb_serial,     // 3: Serial, uses flash unique ID
+  "Picoprobe CMSIS-DAP v1", // Interface descriptor for HID transport
+  "Picoprobe CMSIS-DAP v2", // Interface descriptor for Bulk transport
+  "Picoprobe CDC-ACM UART", // Interface descriptor for CDC
 };
 
 static uint16_t _desc_str[32];
@@ -147,3 +181,69 @@ uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid)
 
   return _desc_str;
 }
+
+/* [incoherent gibbering to make Windows happy] */
+
+//--------------------------------------------------------------------+
+// BOS Descriptor
+//--------------------------------------------------------------------+
+
+/* Microsoft OS 2.0 registry property descriptor
+Per MS requirements https://msdn.microsoft.com/en-us/library/windows/hardware/hh450799(v=vs.85).aspx
+device should create DeviceInterfaceGUIDs. It can be done by driver and
+in case of real PnP solution device should expose MS "Microsoft OS 2.0
+registry property descriptor". Such descriptor can insert any record
+into Windows registry per device/configuration/interface. In our case it
+will insert "DeviceInterfaceGUIDs" multistring property.
+
+
+https://developers.google.com/web/fundamentals/native-hardware/build-for-webusb/
+(Section Microsoft OS compatibility descriptors)
+*/
+#define MS_OS_20_DESC_LEN  0xB2
+
+#define BOS_TOTAL_LEN      (TUD_BOS_DESC_LEN + TUD_BOS_MICROSOFT_OS_DESC_LEN)
+
+uint8_t const desc_bos[] =
+{
+  // total length, number of device caps
+  TUD_BOS_DESCRIPTOR(BOS_TOTAL_LEN, 1),
+
+  // Microsoft OS 2.0 descriptor
+  TUD_BOS_MS_OS_20_DESCRIPTOR(MS_OS_20_DESC_LEN, 1)
+};
+
+uint8_t const desc_ms_os_20[] =
+{
+  // Set header: length, type, windows version, total length
+  U16_TO_U8S_LE(0x000A), U16_TO_U8S_LE(MS_OS_20_SET_HEADER_DESCRIPTOR), U32_TO_U8S_LE(0x06030000), U16_TO_U8S_LE(MS_OS_20_DESC_LEN),
+
+  // Configuration subset header: length, type, configuration index, reserved, configuration total length
+  U16_TO_U8S_LE(0x0008), U16_TO_U8S_LE(MS_OS_20_SUBSET_HEADER_CONFIGURATION), 0, 0, U16_TO_U8S_LE(MS_OS_20_DESC_LEN-0x0A),
+
+  // Function Subset header: length, type, first interface, reserved, subset length
+  U16_TO_U8S_LE(0x0008), U16_TO_U8S_LE(MS_OS_20_SUBSET_HEADER_FUNCTION), ITF_NUM_PROBE, 0, U16_TO_U8S_LE(MS_OS_20_DESC_LEN-0x0A-0x08),
+
+  // MS OS 2.0 Compatible ID descriptor: length, type, compatible ID, sub compatible ID
+  U16_TO_U8S_LE(0x0014), U16_TO_U8S_LE(MS_OS_20_FEATURE_COMPATBLE_ID), 'W', 'I', 'N', 'U', 'S', 'B', 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // sub-compatible
+
+  // MS OS 2.0 Registry property descriptor: length, type
+  U16_TO_U8S_LE(MS_OS_20_DESC_LEN-0x0A-0x08-0x08-0x14), U16_TO_U8S_LE(MS_OS_20_FEATURE_REG_PROPERTY),
+  U16_TO_U8S_LE(0x0007), U16_TO_U8S_LE(0x002A), // wPropertyDataType, wPropertyNameLength and PropertyName "DeviceInterfaceGUIDs\0" in UTF-16
+  'D', 0x00, 'e', 0x00, 'v', 0x00, 'i', 0x00, 'c', 0x00, 'e', 0x00, 'I', 0x00, 'n', 0x00, 't', 0x00, 'e', 0x00,
+  'r', 0x00, 'f', 0x00, 'a', 0x00, 'c', 0x00, 'e', 0x00, 'G', 0x00, 'U', 0x00, 'I', 0x00, 'D', 0x00, 's', 0x00, 0x00, 0x00,
+  U16_TO_U8S_LE(0x0050), // wPropertyDataLength
+  // bPropertyData "{CDB3B5AD-293B-4663-AA36-1AAE46463776}" as a UTF-16 string (b doesn't mean bytes)
+  '{', 0x00, 'C', 0x00, 'D', 0x00, 'B', 0x00, '3', 0x00, 'B', 0x00, '5', 0x00, 'A', 0x00, 'D', 0x00, '-', 0x00,
+  '2', 0x00, '9', 0x00, '3', 0x00, 'B', 0x00, '-', 0x00, '4', 0x00, '6', 0x00, '6', 0x00, '3', 0x00, '-', 0x00,
+  'A', 0x00, 'A', 0x00, '3', 0x00, '6', 0x00, '-', 0x00, '1', 0x00, 'A', 0x00, 'A', 0x00, 'E', 0x00, '4', 0x00,
+  '6', 0x00, '4', 0x00, '6', 0x00, '3', 0x00, '7', 0x00, '7', 0x00, '6', 0x00, '}', 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+TU_VERIFY_STATIC(sizeof(desc_ms_os_20) == MS_OS_20_DESC_LEN, "Incorrect size");
+
+uint8_t const * tud_descriptor_bos_cb(void)
+{
+  return desc_bos;
+}