diff --git a/examples/host/cdc_msc_hid/src/hid_app.c b/examples/host/cdc_msc_hid/src/hid_app.c
index ed53c502d..87e110ab2 100644
--- a/examples/host/cdc_msc_hid/src/hid_app.c
+++ b/examples/host/cdc_msc_hid/src/hid_app.c
@@ -263,7 +263,7 @@ static void process_generic_report(uint8_t dev_addr, uint8_t instance, uint8_t c
 
   if (!rpt_info)
   {
-    printf("Couldn't find the report info for this report !\r\n");
+    printf("Couldn't find report info !\r\n");
     return;
   }
 
diff --git a/hw/bsp/imxrt/family.c b/hw/bsp/imxrt/family.c
index 52d3bb91b..46adabf0a 100644
--- a/hw/bsp/imxrt/family.c
+++ b/hw/bsp/imxrt/family.c
@@ -131,7 +131,10 @@ void board_init(void)
     freq = CLOCK_GetOscFreq() / (CLOCK_GetDiv(kCLOCK_UartDiv) + 1U);
   }
 
-  LPUART_Init(UART_PORT, &uart_config, freq);
+  if ( kStatus_Success != LPUART_Init(UART_PORT, &uart_config, freq) ) {
+    // failed to init uart, probably baudrate is not supported
+    // TU_BREAKPOINT();
+  }
 
   //------------- USB -------------//
   // Note: RT105x RT106x and later have dual USB controllers.
diff --git a/src/class/hid/hid_host.c b/src/class/hid/hid_host.c
index 3a491937a..6abe298e5 100644
--- a/src/class/hid/hid_host.c
+++ b/src/class/hid/hid_host.c
@@ -72,7 +72,7 @@ tu_static hidh_interface_t _hidh_itf[CFG_TUH_HID];
 TU_ATTR_ALWAYS_INLINE static inline
 hidh_interface_t* get_hid_itf(uint8_t daddr, uint8_t idx)
 {
-  TU_ASSERT(daddr && idx < CFG_TUH_HID, NULL);
+  TU_ASSERT(daddr > 0 && idx < CFG_TUH_HID, NULL);
   hidh_interface_t* p_hid = &_hidh_itf[idx];
   return (p_hid->daddr == daddr) ? p_hid : NULL;
 }
diff --git a/src/host/hcd.h b/src/host/hcd.h
index 623c12a12..f4e76f9ef 100644
--- a/src/host/hcd.h
+++ b/src/host/hcd.h
@@ -39,8 +39,10 @@
 // Configuration
 //--------------------------------------------------------------------+
 
+// Max number of endpoints per device
+// TODO optimize memory usage
 #ifndef CFG_TUH_ENDPOINT_MAX
-  #define CFG_TUH_ENDPOINT_MAX   (CFG_TUH_HUB + CFG_TUH_HID*2 + CFG_TUH_MSC*2 + CFG_TUH_CDC*3)
+  #define CFG_TUH_ENDPOINT_MAX   16
 //  #ifdef TUP_HCD_ENDPOINT_MAX
 //    #define CFG_TUH_ENDPPOINT_MAX   TUP_HCD_ENDPOINT_MAX
 //  #else
diff --git a/src/portable/ehci/ehci.c b/src/portable/ehci/ehci.c
index 69e59ce65..080ee9bbc 100644
--- a/src/portable/ehci/ehci.c
+++ b/src/portable/ehci/ehci.c
@@ -58,7 +58,8 @@
 
 #define FRAMELIST_SIZE                  (1024 >> FRAMELIST_SIZE_BIT_VALUE)
 
-#define QHD_MAX      (CFG_TUH_DEVICE_MAX*CFG_TUH_ENDPOINT_MAX)
+// Total queue head pool. TODO should be user configurable and more optimize memory usage in the future
+#define QHD_MAX      (CFG_TUH_DEVICE_MAX*CFG_TUH_ENDPOINT_MAX + CFG_TUH_HUB)
 #define QTD_MAX      QHD_MAX
 
 typedef struct
@@ -138,17 +139,6 @@ static inline ehci_qtd_t* qtd_control(uint8_t dev_addr)
 static inline ehci_qhd_t* qhd_next (ehci_qhd_t const * p_qhd);
 static inline ehci_qhd_t* qhd_find_free (void);
 static inline ehci_qhd_t* qhd_get_from_addr (uint8_t dev_addr, uint8_t ep_addr);
-
-// determine if a queue head has bus-related error
-static inline bool qhd_has_xact_error (ehci_qhd_t * p_qhd)
-{
-  volatile ehci_qtd_t *qtd_overlay = &p_qhd->qtd_overlay;
-
-  // Error count = 0 often occurs when device disconnected
-  return (qtd_overlay->err_count == 0 || qtd_overlay->buffer_err || qtd_overlay->babble_err || qtd_overlay->xact_err);
-  //qtd_overlay->non_hs_period_missed_uframe || qtd_overlay->pingstate_err TODO split transaction error
-}
-
 static void qhd_init(ehci_qhd_t *p_qhd, uint8_t dev_addr, tusb_desc_endpoint_t const * ep_desc);
 
 static inline ehci_qtd_t* qtd_find_free (void);
@@ -392,15 +382,7 @@ bool hcd_edpt_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_endpoint_t const
   TU_ASSERT (ep_desc->bmAttributes.xfer != TUSB_XFER_ISOCHRONOUS);
 
   //------------- Prepare Queue Head -------------//
-  ehci_qhd_t * p_qhd;
-
-  if ( ep_desc->bEndpointAddress == 0 )
-  {
-    p_qhd = qhd_control(dev_addr);
-  }else
-  {
-    p_qhd = qhd_find_free();
-  }
+  ehci_qhd_t *p_qhd = (ep_desc->bEndpointAddress == 0) ? qhd_control(dev_addr) : qhd_find_free();
   TU_ASSERT(p_qhd);
 
   qhd_init(p_qhd, dev_addr, ep_desc);
@@ -622,18 +604,23 @@ static void period_list_xfer_complete_isr(uint8_t hostid, uint32_t interval_ms)
 
 static void qhd_xfer_error_isr(ehci_qhd_t * p_qhd)
 {
-  if ( (p_qhd->dev_addr != 0 && p_qhd->qtd_overlay.halted) || // addr0 cannot be protocol STALL
-        qhd_has_xact_error(p_qhd) )
-  {
-    // current qhd has error in transaction
-    xfer_result_t error_event;
+  volatile ehci_qtd_t *qtd_overlay = &p_qhd->qtd_overlay;
 
-    // no error bits are set, endpoint is halted due to STALL
-    error_event = qhd_has_xact_error(p_qhd) ? XFER_RESULT_FAILED : XFER_RESULT_STALLED;
+  // TD has error
+  if (qtd_overlay->halted) {
+    xfer_result_t xfer_result;
+
+    if (qtd_overlay->err_count == 0 || qtd_overlay->buffer_err || qtd_overlay->babble_err || qtd_overlay->xact_err) {
+      // Error count = 0 often occurs when device disconnected, or other bus-related error
+      xfer_result = XFER_RESULT_FAILED;
+    }else {
+      // no error bits are set, endpoint is halted due to STALL
+      xfer_result = XFER_RESULT_STALLED;
+    }
 
     p_qhd->total_xferred_bytes += p_qhd->p_qtd_list_head->expected_bytes - p_qhd->p_qtd_list_head->total_bytes;
 
-//    if ( XFER_RESULT_FAILED == error_event ) {
+//    if (XFER_RESULT_FAILED == xfer_result ) {
 //      TU_BREAKPOINT(); // TODO skip unplugged device
 //    }
 
@@ -655,7 +642,8 @@ static void qhd_xfer_error_isr(ehci_qhd_t * p_qhd)
     }
 
     // call USBH callback
-    hcd_event_xfer_complete(p_qhd->dev_addr, tu_edpt_addr(p_qhd->ep_number, p_qhd->pid == EHCI_PID_IN ? 1 : 0), p_qhd->total_xferred_bytes, error_event, true);
+    uint8_t const ep_addr = tu_edpt_addr(p_qhd->ep_number, p_qhd->pid == EHCI_PID_IN ? 1 : 0);
+    hcd_event_xfer_complete(p_qhd->dev_addr, ep_addr, p_qhd->total_xferred_bytes, xfer_result, true);
 
     p_qhd->total_xferred_bytes = 0;
   }