diff --git a/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject b/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject
index d61b82cfa..fbb8841b7 100644
--- a/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject
+++ b/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject
@@ -22,6 +22,7 @@
       c_user_include_directories="../../src;$(rootDir)/hw/cmsis/Include;$(rootDir)/hw;$(rootDir)/src;$(asf4Dir);$(asf4Dir)/include;$(asf4Dir)/config;$(asf4Dir)/hri;$(asf4Dir)/hal/include;$(asf4Dir)/hal/utils/include;$(asf4Dir)/hpl/port;$(asf4Dir)/hpl/gclk;$(asf4Dir)/hpl/pm"
       debug_register_definition_file="ATSAMD21G18A_Registers.xml"
       debug_target_connection="J-Link"
+      gcc_enable_all_warnings="Yes"
       gcc_entry_point="Reset_Handler"
       link_use_linker_script_file="No"
       linker_memory_map_file="$(ProjectDir)/ATSAMD21G18A_MemoryMap.xml"
diff --git a/src/common/tusb_fifo.h b/src/common/tusb_fifo.h
index 61d92b602..e88c2ac6d 100644
--- a/src/common/tusb_fifo.h
+++ b/src/common/tusb_fifo.h
@@ -67,13 +67,12 @@ typedef struct
            uint8_t* buffer    ; ///< buffer pointer
            uint16_t depth     ; ///< max items
            uint16_t item_size ; ///< size of each item
+           bool overwritable  ;
 
   volatile uint16_t count     ; ///< number of items in queue
   volatile uint16_t wr_idx    ; ///< write pointer
   volatile uint16_t rd_idx    ; ///< read pointer
 
-           bool overwritable  ;
-
 #if CFG_FIFO_MUTEX
   tu_fifo_mutex_t mutex;
 #endif
diff --git a/src/device/usbd.c b/src/device/usbd.c
index ddb63cebb..78eebf76b 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -161,8 +161,9 @@ enum { USBD_CLASS_DRIVER_COUNT = sizeof(usbd_class_drivers) / sizeof(usbd_class_
 //--------------------------------------------------------------------+
 OSAL_TASK_DEF(_usbd_task_def, "usbd", usbd_task, CFG_TUD_TASK_PRIO, CFG_TUD_TASK_STACK_SZ);
 
-/*------------- event queue -------------*/
-OSAL_QUEUE_DEF(_usbd_qdef, CFG_TUD_TASK_QUEUE_SZ, dcd_event_t);
+// Event queue
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+OSAL_QUEUE_DEF(OPT_MODE_DEVICE, _usbd_qdef, CFG_TUD_TASK_QUEUE_SZ, dcd_event_t);
 static osal_queue_t _usbd_q;
 
 //--------------------------------------------------------------------+
@@ -188,11 +189,11 @@ bool tud_mounted(void)
 //--------------------------------------------------------------------+
 // USBD Task
 //--------------------------------------------------------------------+
-tusb_error_t usbd_init (void)
+bool usbd_init (void)
 {
   // Init device queue & task
   _usbd_q = osal_queue_create(&_usbd_qdef);
-  TU_VERIFY(_usbd_q, TUSB_ERROR_OSAL_QUEUE_FAILED);
+  TU_ASSERT(_usbd_q != NULL);
 
   osal_task_create(&_usbd_task_def);
 
@@ -200,17 +201,10 @@ tusb_error_t usbd_init (void)
   for (uint8_t i = 0; i < USBD_CLASS_DRIVER_COUNT; i++) usbd_class_drivers[i].init();
 
   // Init device controller driver
-  #if (CFG_TUSB_RHPORT0_MODE & OPT_MODE_DEVICE)
-  dcd_init(0);
-  dcd_int_enable(0);
-  #endif
+  TU_ASSERT(dcd_init(TUD_OPT_RHPORT));
+  dcd_int_enable(TUD_OPT_RHPORT);
 
-  #if (CFG_TUSB_RHPORT1_MODE & OPT_MODE_DEVICE)
-  dcd_init(1);
-  dcd_int_enable(1);
-  #endif
-
-  return TUSB_ERROR_NONE;
+  return true;
 }
 
 static void usbd_reset(uint8_t rhport)
@@ -268,14 +262,14 @@ static void usbd_task_body(void)
       break;
 
       case DCD_EVENT_BUS_RESET:
-        // note: if task is too slow, we could clear the event of the new attached
         usbd_reset(event.rhport);
+        // TODO remove since if task is too slow, we could clear the event of the new attached
         osal_queue_reset(_usbd_q);
       break;
 
       case DCD_EVENT_UNPLUGGED:
-        // note: if task is too slow, we could clear the event of the new attached
         usbd_reset(event.rhport);
+        // TODO remove since if task is too slow, we could clear the event of the new attached
         osal_queue_reset(_usbd_q);
 
         tud_umount_cb();    // invoke callback
@@ -587,6 +581,11 @@ void dcd_event_handler(dcd_event_t const * event, bool in_isr)
       TU_ASSERT(event->xfer_complete.result == XFER_RESULT_SUCCESS,);
     break;
 
+    // Not an DCD event, just a convenient way to defer ISR function should we need
+    case USBD_EVT_FUNC_CALL:
+      osal_queue_send(_usbd_q, event, in_isr);
+    break;
+
     default: break;
   }
 }
@@ -622,6 +621,8 @@ void dcd_event_xfer_complete (uint8_t rhport, uint8_t ep_addr, uint32_t xferred_
 //--------------------------------------------------------------------+
 // Helper
 //--------------------------------------------------------------------+
+
+// Helper to parse an pair of endpoint descriptors (IN & OUT)
 tusb_error_t usbd_open_edpt_pair(uint8_t rhport, tusb_desc_endpoint_t const* p_desc_ep, uint8_t xfer_type, uint8_t* ep_out, uint8_t* ep_in)
 {
   for(int i=0; i<2; i++)
@@ -645,7 +646,8 @@ tusb_error_t usbd_open_edpt_pair(uint8_t rhport, tusb_desc_endpoint_t const* p_d
   return TUSB_ERROR_NONE;
 }
 
-void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr )
+// Helper to defer an isr function
+void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr)
 {
   dcd_event_t event =
   {
@@ -656,7 +658,7 @@ void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr )
   event.func_call.func  = func;
   event.func_call.param = param;
 
-  osal_queue_send(_usbd_q, &event, in_isr);
+  dcd_event_handler(&event, in_isr);
 }
 
 #endif
diff --git a/src/device/usbd_control.c b/src/device/usbd_control.c
index ebeaaaa4d..ae7e894b7 100644
--- a/src/device/usbd_control.c
+++ b/src/device/usbd_control.c
@@ -83,7 +83,6 @@ bool usbd_control_status(uint8_t rhport, tusb_control_request_t const * request)
   return dcd_edpt_xfer(rhport, request->bmRequestType_bit.direction ? EDPT_CTRL_OUT : EDPT_CTRL_IN, NULL, 0);
 }
 
-
 // Each transaction is up to endpoint0's max packet size
 static bool start_control_data_xact(uint8_t rhport)
 {
diff --git a/src/device/usbd_pvt.h b/src/device/usbd_pvt.h
index 30f010887..cbe5017bb 100644
--- a/src/device/usbd_pvt.h
+++ b/src/device/usbd_pvt.h
@@ -51,8 +51,8 @@ extern tud_desc_set_t const* usbd_desc_set;
 //--------------------------------------------------------------------+
 // INTERNAL API for stack management
 //--------------------------------------------------------------------+
-tusb_error_t usbd_init (void);
-void         usbd_task (void* param);
+bool usbd_init (void);
+void usbd_task (void* param);
 
 
 // Carry out Data and Status stage of control transfer
diff --git a/src/host/usbh.h b/src/host/usbh.h
index 22fdef162..56efb6ff7 100644
--- a/src/host/usbh.h
+++ b/src/host/usbh.h
@@ -97,14 +97,11 @@ ATTR_WEAK void    tuh_device_mount_failed_cb(tusb_error_t error, tusb_desc_devic
 //--------------------------------------------------------------------+
 #ifdef _TINY_USB_SOURCE_FILE_
 
-
 void usbh_enumeration_task(void* param);
 tusb_error_t usbh_init(void);
 
 tusb_error_t usbh_control_xfer_subtask(uint8_t dev_addr, uint8_t bmRequestType, uint8_t bRequest,
                                        uint16_t wValue, uint16_t wIndex, uint16_t wLength, uint8_t* data);
-
-
 #endif
 
 #ifdef __cplusplus
diff --git a/src/osal/osal_freertos.h b/src/osal/osal_freertos.h
index 52cadd798..704aafd64 100644
--- a/src/osal/osal_freertos.h
+++ b/src/osal/osal_freertos.h
@@ -139,7 +139,9 @@ static inline bool osal_mutex_unlock(osal_mutex_t mutex_hdl)
 //--------------------------------------------------------------------+
 // QUEUE API
 //--------------------------------------------------------------------+
-#define OSAL_QUEUE_DEF(_name, _depth, _type) \
+
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+#define OSAL_QUEUE_DEF(_role, _name, _depth, _type) \
   static _type _name##_##buf[_depth];\
   osal_queue_def_t _name = { .depth = _depth, .item_sz = sizeof(_type), .buf = _name##_##buf };
 
diff --git a/src/osal/osal_mynewt.h b/src/osal/osal_mynewt.h
index cb09680e0..62b5b45e8 100644
--- a/src/osal/osal_mynewt.h
+++ b/src/osal/osal_mynewt.h
@@ -75,7 +75,9 @@ static inline void osal_task_delay(uint32_t msec)
 //--------------------------------------------------------------------+
 // QUEUE API
 //--------------------------------------------------------------------+
-#define OSAL_QUEUE_DEF(_name, _depth, _type) \
+
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+#define OSAL_QUEUE_DEF(_role, _name, _depth, _type) \
   static _type _name##_##buf[_depth];\
   static struct os_event* _name##_##evbuf[_depth];\
   osal_queue_def_t _name = { .depth = _depth, .item_sz = sizeof(_type), .buf = _name##_##buf, .evbuf =  _name##_##evbuf};\
diff --git a/src/osal/osal_none.h b/src/osal/osal_none.h
index 40ecb9c37..4d5a4dd57 100644
--- a/src/osal/osal_none.h
+++ b/src/osal/osal_none.h
@@ -93,12 +93,11 @@ static inline void osal_semaphore_reset(osal_semaphore_t sem_hdl)
 static inline tusb_error_t osal_semaphore_wait(osal_semaphore_t sem_hdl, uint32_t msec) {
   (void) msec;
   while (true) {
-      while (sem_hdl->count == 0) {
-      }
-      if (sem_hdl->count == 0) {
-          sem_hdl->count--;
-          break;
-      }
+    while (sem_hdl->count == 0) { }
+    if (sem_hdl->count == 0) {
+      sem_hdl->count--;
+      break;
+    }
   }
   return TUSB_ERROR_NONE;
 }
@@ -124,40 +123,97 @@ static inline osal_mutex_t osal_mutex_create(osal_mutex_def_t* mdef)
 //--------------------------------------------------------------------+
 #include "common/tusb_fifo.h"
 
-#define OSAL_QUEUE_DEF(_name, _depth, _type)    TU_FIFO_DEF(_name, _depth, _type, false)
+// extern to avoid including dcd.h and hcd.h
+#if TUSB_OPT_DEVICE_ENABLED
+extern void dcd_int_disable(uint8_t rhport);
+extern void dcd_int_enable(uint8_t rhport);
+#endif
 
-typedef tu_fifo_t  osal_queue_def_t;
-typedef tu_fifo_t* osal_queue_t;
+#if MODE_HOST_SUPPORTED
+extern void hcd_int_disable(uint8_t rhport);
+extern void hcd_int_enable(uint8_t rhport);
+#endif
+
+typedef struct
+{
+    uint8_t role; // device or host
+    tu_fifo_t ff;
+}osal_queue_def_t;
+
+typedef osal_queue_def_t* osal_queue_t;
+
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+#define OSAL_QUEUE_DEF(_role, _name, _depth, _type) \
+  uint8_t _name##_buf[_depth*sizeof(_type)];        \
+  osal_queue_def_t _name = {                        \
+    .role = _role,                                  \
+    .ff = {                                         \
+      .buffer       = _name##_buf,                  \
+      .depth        = _depth,                       \
+      .item_size    = sizeof(_type),                \
+      .overwritable = false,                        \
+    }\
+  }
+
+// lock queue by disable usb isr
+static inline void _osal_q_lock(osal_queue_t qhdl)
+{
+#if TUSB_OPT_DEVICE_ENABLED
+  if (qhdl->role == OPT_MODE_DEVICE) dcd_int_disable(TUD_OPT_RHPORT);
+#endif
+
+#if MODE_HOST_SUPPORTED
+  if (qhdl->role == OPT_MODE_HOST) hcd_int_disable(TUH_OPT_RHPORT);
+#endif
+}
+
+// unlock queue
+static inline void _osal_q_unlock(osal_queue_t qhdl)
+{
+#if TUSB_OPT_DEVICE_ENABLED
+  if (qhdl->role == OPT_MODE_DEVICE) dcd_int_enable(TUD_OPT_RHPORT);
+#endif
+
+#if MODE_HOST_SUPPORTED
+  if (qhdl->role == OPT_MODE_HOST) hcd_int_enable(TUH_OPT_RHPORT);
+#endif
+}
 
 static inline osal_queue_t osal_queue_create(osal_queue_def_t* qdef)
 {
-  tu_fifo_clear(qdef);
+  tu_fifo_clear(&qdef->ff);
   return (osal_queue_t) qdef;
 }
 
-static inline bool osal_queue_send(osal_queue_t const queue_hdl, void const * data, bool in_isr)
+static inline bool osal_queue_send(osal_queue_t const qhdl, void const * data, bool in_isr)
 {
   if (!in_isr) {
-    tusb_hal_int_disable_all();
+    _osal_q_lock(qhdl);
   }
-  bool success = tu_fifo_write( (tu_fifo_t*) queue_hdl, data);
+
+  bool success = tu_fifo_write(&qhdl->ff, data);
+
   if (!in_isr) {
-    tusb_hal_int_enable_all();
+    _osal_q_unlock(qhdl);
   }
+
   return success;
 }
 
-static inline void osal_queue_reset(osal_queue_t const queue_hdl)
+static inline void osal_queue_reset(osal_queue_t const qhdl)
 {
   // tusb_hal_int_disable_all();
-  tu_fifo_clear( (tu_fifo_t*) queue_hdl);
+  tu_fifo_clear(&qhdl->ff);
   // tusb_hal_int_enable_all();
 }
 
-static inline bool osal_queue_receive(osal_queue_t const queue_hdl, void* data) {
-  tusb_hal_int_disable_all();
-  bool success = tu_fifo_read(queue_hdl, data);
-  tusb_hal_int_enable_all();
+// non blocking
+static inline bool osal_queue_receive(osal_queue_t const qhdl, void* data)
+{
+  _osal_q_lock(qhdl);
+  bool success = tu_fifo_read(&qhdl->ff, data);
+  _osal_q_unlock(qhdl);
+
   return success;
 }
 
diff --git a/src/portable/nordic/nrf5x/hal_nrf5x.c b/src/portable/nordic/nrf5x/hal_nrf5x.c
index 4cbcd1788..f0a0b9632 100644
--- a/src/portable/nordic/nrf5x/hal_nrf5x.c
+++ b/src/portable/nordic/nrf5x/hal_nrf5x.c
@@ -145,7 +145,6 @@ void tusb_hal_nrf_power_event (uint32_t event)
         /* Enable the peripheral */
         // ERRATA 171, 187, 166
 
-        // Somehow Errata 187 check failed for pca10056 1.0.0 (2018.19)
         if ( nrf_drv_usbd_errata_187() )
         {
           // CRITICAL_REGION_ENTER();
@@ -209,7 +208,6 @@ void tusb_hal_nrf_power_event (uint32_t event)
         // CRITICAL_REGION_EXIT();
       }
 
-      // Somehow Errata 187 check failed for pca10056 1.0.0 (2018.19)
       if ( nrf_drv_usbd_errata_187() )
       {
         // CRITICAL_REGION_ENTER();
@@ -247,9 +245,7 @@ void tusb_hal_nrf_power_event (uint32_t event)
       NVIC_EnableIRQ(USBD_IRQn);
 
       // Wait for HFCLK
-      while ( !hfclk_running() )
-      {
-      }
+      while ( !hfclk_running() ) { }
 
       // Enable pull up
       nrf_usbd_pullup_enable();
diff --git a/src/portable/nordic/nrf5x/nrf_drv_usbd_errata.h b/src/portable/nordic/nrf5x/nrf_drv_usbd_errata.h
index f8c554f08..4a76e7eaa 100644
--- a/src/portable/nordic/nrf5x/nrf_drv_usbd_errata.h
+++ b/src/portable/nordic/nrf5x/nrf_drv_usbd_errata.h
@@ -1,30 +1,30 @@
 /**
  * Copyright (c) 2017 - 2018, Nordic Semiconductor ASA
- * 
+ *
  * All rights reserved.
- * 
+ *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
- * 
+ *
  * 1. Redistributions of source code must retain the above copyright notice, this
  *    list of conditions and the following disclaimer.
- * 
+ *
  * 2. Redistributions in binary form, except as embedded into a Nordic
  *    Semiconductor ASA integrated circuit in a product or a software update for
  *    such product, must reproduce the above copyright notice, this list of
  *    conditions and the following disclaimer in the documentation and/or other
  *    materials provided with the distribution.
- * 
+ *
  * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
  *    contributors may be used to endorse or promote products derived from this
  *    software without specific prior written permission.
- * 
+ *
  * 4. This software, with or without modification, must only be used with a
  *    Nordic Semiconductor ASA integrated circuit.
- * 
+ *
  * 5. Any software provided in binary form under this license must not be reverse
  *    engineered, decompiled, modified and/or disassembled.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
@@ -35,7 +35,7 @@
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- * 
+ *
  */
 
 #ifndef NRF_DRV_USBD_ERRATA_H__
@@ -68,34 +68,47 @@
  */
 static inline bool nrf_drv_usbd_errata_type_52840(void)
 {
-    return ((((*(uint32_t *)0xF0000FE0) & 0xFF) == 0x08) &&
-        (((*(uint32_t *)0xF0000FE4) & 0x0F) == 0x0));
+    return (*(uint32_t *)0x10000130UL == 0x8UL);
 }
 
 /**
- * @brief Internal auxiliary function to check if the program is running on first sample of
- *        NRF52840 chip
- * @retval true  It is NRF52480 chip and it is first sample version
+ * @brief Internal auxiliary function to check if the program is running on Engineering A revision
+ * @retval true  It is NRF52480 chip and it is Engineering A revision
  * @retval false It is other chip
  */
-static inline bool nrf_drv_usbd_errata_type_52840_proto1(void)
+static inline bool nrf_drv_usbd_errata_type_52840_eng_a(void)
 {
-    return ( nrf_drv_usbd_errata_type_52840() &&
-               ( ((*(uint32_t *)0xF0000FE8) & 0xF0) == 0x00 ) &&
-               ( ((*(uint32_t *)0xF0000FEC) & 0xF0) == 0x00 ) );
+    return (nrf_drv_usbd_errata_type_52840() && (*(uint32_t *)0x10000134UL == 0x0UL));
 }
 
 /**
- * @brief Internal auxiliary function to check if the program is running on first final product of
- *        NRF52840 chip
- * @retval true  It is NRF52480 chip and it is first final product
+ * @brief Internal auxiliary function to check if the program is running on Engineering B revision
+ * @retval true  It is NRF52480 chip and it is Engineering B revision
  * @retval false It is other chip
  */
-static inline bool nrf_drv_usbd_errata_type_52840_fp1(void)
+static inline bool nrf_drv_usbd_errata_type_52840_eng_b(void)
 {
-    return ( nrf_drv_usbd_errata_type_52840() &&
-               ( ((*(uint32_t *)0xF0000FE8) & 0xF0) == 0x20 ) &&
-               ( ((*(uint32_t *)0xF0000FEC) & 0xF0) == 0x00 ) );
+    return (nrf_drv_usbd_errata_type_52840() && (*(uint32_t *)0x10000134UL == 0x1UL));
+}
+
+/**
+ * @brief Internal auxiliary function to check if the program is running on Engineering C revision
+ * @retval true  It is NRF52480 chip and it is Engineering C revision
+ * @retval false It is other chip
+ */
+static inline bool nrf_drv_usbd_errata_type_52840_eng_c(void)
+{
+    return (nrf_drv_usbd_errata_type_52840() && (*(uint32_t *)0x10000134UL == 0x2UL));
+}
+
+/**
+ * @brief Internal auxiliary function to check if the program is running on Engineering D revision
+ * @retval true  It is NRF52480 chip and it is Engineering D revision
+ * @retval false It is other chip
+ */
+static inline bool nrf_drv_usbd_errata_type_52840_eng_d(void)
+{
+    return (nrf_drv_usbd_errata_type_52840() && (*(uint32_t *)0x10000134UL == 0x3UL));
 }
 
 /**
@@ -108,7 +121,7 @@ static inline bool nrf_drv_usbd_errata_type_52840_fp1(void)
  */
 static inline bool nrf_drv_usbd_errata_104(void)
 {
-    return NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_proto1();
+    return (NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_eng_a());
 }
 
 /**
@@ -121,7 +134,7 @@ static inline bool nrf_drv_usbd_errata_104(void)
  */
 static inline bool nrf_drv_usbd_errata_154(void)
 {
-    return NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_proto1();
+    return (NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_eng_a());
 }
 
 /**
@@ -134,7 +147,7 @@ static inline bool nrf_drv_usbd_errata_154(void)
  */
 static inline bool nrf_drv_usbd_errata_166(void)
 {
-    return NRF_DRV_USBD_ERRATA_ENABLE && true;
+    return (NRF_DRV_USBD_ERRATA_ENABLE && true);
 }
 
 /**
@@ -147,7 +160,7 @@ static inline bool nrf_drv_usbd_errata_166(void)
  */
 static inline bool nrf_drv_usbd_errata_171(void)
 {
-    return NRF_DRV_USBD_ERRATA_ENABLE && true;
+    return (NRF_DRV_USBD_ERRATA_ENABLE && true);
 }
 
 /**
@@ -160,20 +173,11 @@ static inline bool nrf_drv_usbd_errata_171(void)
  */
 static inline bool nrf_drv_usbd_errata_187(void)
 {
-    return NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_fp1();
-}
-
-/**
- * @brief Function to check if chip requires errata ???
- *
- * Errata: SIZE.EPOUT not writable
- *
- * @retval true  Errata should be implemented
- * @retval false Errata should not be implemented
- */
-static inline bool nrf_drv_usbd_errata_sizeepout_rw(void)
-{
-    return NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_proto1();
+    return (NRF_DRV_USBD_ERRATA_ENABLE && 
+            (nrf_drv_usbd_errata_type_52840_eng_b() ||
+             nrf_drv_usbd_errata_type_52840_eng_c() ||
+             nrf_drv_usbd_errata_type_52840_eng_d())
+           );
 }
 
 /**
@@ -186,7 +190,20 @@ static inline bool nrf_drv_usbd_errata_sizeepout_rw(void)
  */
 static inline bool nrf_drv_usb_errata_199(void)
 {
-    return NRF_DRV_USBD_ERRATA_ENABLE && true;
+    return (NRF_DRV_USBD_ERRATA_ENABLE && true);
+}
+
+/**
+ * @brief Function to check if chip requires errata 200
+ *
+ * Errata: SIZE.EPOUT not writable
+ *
+ * @retval true  Errata should be implemented
+ * @retval false Errata should not be implemented
+ */
+static inline bool nrf_drv_usbd_errata_200(void)
+{
+    return (NRF_DRV_USBD_ERRATA_ENABLE && nrf_drv_usbd_errata_type_52840_eng_a());
 }
 
 /** @} */
diff --git a/src/tusb.c b/src/tusb.c
index 81c4907fb..fe4dbb2c1 100644
--- a/src/tusb.c
+++ b/src/tusb.c
@@ -47,17 +47,17 @@
 
 static bool _initialized = false;
 
-tusb_error_t tusb_init(void)
+bool tusb_init(void)
 {
   // skip if already initialized
-  if (_initialized) return TUSB_ERROR_NONE;
+  if (_initialized) return true;
 
 #if MODE_HOST_SUPPORTED
-  TU_ASSERT_ERR( usbh_init() ); // host stack init
+  TU_VERIFY( usbh_init() == TUSB_ERROR_NONE ); // init host stack
 #endif
 
 #if TUSB_OPT_DEVICE_ENABLED
-  TU_ASSERT_ERR ( usbd_init() ); // device stack init
+  TU_VERIFY ( usbd_init() ); // init device stack
 #endif
 
   _initialized = true;
diff --git a/src/tusb.h b/src/tusb.h
index c0246ccc8..4f8918ce5 100644
--- a/src/tusb.h
+++ b/src/tusb.h
@@ -101,16 +101,14 @@
 /** \ingroup group_application_api
  *  @{ */
 
-/** \brief Initialize the usb stack
- * \return Error Code of the \ref TUSB_ERROR enum
- * \note   Function will initialize the stack according to configuration in the configure file (tusb_config.h)
- */
-tusb_error_t tusb_init(void);
+// Initialize device/host stack according to tusb_config.h
+// return true if success
+bool tusb_init(void);
 
 #if CFG_TUSB_OS == OPT_OS_NONE
 /** \brief Run all tinyusb's internal tasks (e.g host task, device task).
  * \note   This function is only required when using no RTOS (\ref CFG_TUSB_OS == OPT_OS_NONE). All the stack functions
- *         & callback are invoked within this function, so it should be called periodically within the mainloop
+ *         & callback are invoked within this function. This should be called periodically within the mainloop
  *
     @code
     int main(void)
diff --git a/src/tusb_hal.h b/src/tusb_hal.h
index 301e8c2f2..e02ff480d 100644
--- a/src/tusb_hal.h
+++ b/src/tusb_hal.h
@@ -53,40 +53,9 @@ extern "C" {
 //--------------------------------------------------------------------+
 
 // Only required to implement if using No RTOS (osal_none)
+// TODO could be remove
 uint32_t tusb_hal_millis(void);
 
-// TODO remove
-extern void dcd_int_enable (uint8_t rhport);
-extern void dcd_int_disable(uint8_t rhport);
-
-// Enable all ports' interrupt
-// TODO remove
-static inline void tusb_hal_int_enable_all(void)
-{
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_enable(0);
-#endif
-
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_enable(1);
-#endif
-}
-
-// Disable all ports' interrupt
-// TODO remove
-static inline void tusb_hal_int_disable_all(void)
-{
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_disable(0);
-#endif
-
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_disable(1);
-#endif
-}
-
-
-
 #ifdef __cplusplus
  }
 #endif
diff --git a/src/tusb_option.h b/src/tusb_option.h
index c558b30ff..6b84db21c 100644
--- a/src/tusb_option.h
+++ b/src/tusb_option.h
@@ -123,7 +123,6 @@
 // Which roothub port is configured as device
 #define TUD_OPT_RHPORT          ( (CFG_TUSB_RHPORT0_MODE & OPT_MODE_DEVICE) ? 0 : ((CFG_TUSB_RHPORT1_MODE & OPT_MODE_DEVICE) ? 1 : -1) )
 
-
 #if TUD_OPT_RHPORT == 0
 #define TUD_OPT_HIGH_SPEED      ( CFG_TUSB_RHPORT0_MODE & OPT_MODE_HIGH_SPEED )
 #else