diff --git a/examples/device/audio_4_channel_mic/src/main.c b/examples/device/audio_4_channel_mic/src/main.c
index 26d8c48c5d..2b9c5143de 100644
--- a/examples/device/audio_4_channel_mic/src/main.c
+++ b/examples/device/audio_4_channel_mic/src/main.c
@@ -99,9 +99,6 @@ int main(void)
     led_blinking_task();
     audio_task();
   }
-
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
@@ -290,7 +287,7 @@ bool tud_audio_get_req_entity_cb(uint8_t rhport, tusb_control_request_t const *
 
         // Those are dummy values for now
         ret.bNrChannels = 1;
-        ret.bmChannelConfig = 0;
+        ret.bmChannelConfig = (audio_channel_config_t) 0;
         ret.iChannelNames = 0;
 
         TU_LOG2("    Get terminal connector\r\n");
diff --git a/examples/device/audio_test/src/main.c b/examples/device/audio_test/src/main.c
index f9cc63cdd2..b5ca41d362 100644
--- a/examples/device/audio_test/src/main.c
+++ b/examples/device/audio_test/src/main.c
@@ -100,9 +100,6 @@ int main(void)
     led_blinking_task();
     audio_task();
   }
-
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
@@ -291,7 +288,7 @@ bool tud_audio_get_req_entity_cb(uint8_t rhport, tusb_control_request_t const *
 
         // Those are dummy values for now
         ret.bNrChannels = 1;
-        ret.bmChannelConfig = 0;
+        ret.bmChannelConfig = (audio_channel_config_t) 0;
         ret.iChannelNames = 0;
 
         TU_LOG2("    Get terminal connector\r\n");
diff --git a/examples/device/board_test/src/main.c b/examples/device/board_test/src/main.c
index e8e393717a..3f8d55c521 100644
--- a/examples/device/board_test/src/main.c
+++ b/examples/device/board_test/src/main.c
@@ -74,8 +74,6 @@ int main(void)
       board_uart_write(&ch, 1);
     }
   }
-
-  return 0;
 }
 
 #if CFG_TUSB_MCU == OPT_MCU_ESP32S2 || CFG_TUSB_MCU == OPT_MCU_ESP32S3
diff --git a/examples/device/cdc_dual_ports/src/main.c b/examples/device/cdc_dual_ports/src/main.c
index c0296191b0..70eaea85d9 100644
--- a/examples/device/cdc_dual_ports/src/main.c
+++ b/examples/device/cdc_dual_ports/src/main.c
@@ -47,8 +47,6 @@ int main(void)
     tud_task(); // tinyusb device task
     cdc_task();
   }
-
-  return 0;
 }
 
 // echo to either Serial0 or Serial1
diff --git a/examples/device/cdc_msc/src/main.c b/examples/device/cdc_msc/src/main.c
index 207dd728c2..6dad73cbf1 100644
--- a/examples/device/cdc_msc/src/main.c
+++ b/examples/device/cdc_msc/src/main.c
@@ -65,8 +65,6 @@ int main(void)
 
     cdc_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/dfu/src/main.c b/examples/device/dfu/src/main.c
index 6bb183819c..5f37f25e16 100644
--- a/examples/device/dfu/src/main.c
+++ b/examples/device/dfu/src/main.c
@@ -82,8 +82,6 @@ int main(void)
     tud_task(); // tinyusb device task
     led_blinking_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/dfu_runtime/src/main.c b/examples/device/dfu_runtime/src/main.c
index 4ec2fa31da..4ec3cb1889 100644
--- a/examples/device/dfu_runtime/src/main.c
+++ b/examples/device/dfu_runtime/src/main.c
@@ -77,8 +77,6 @@ int main(void)
     tud_task(); // tinyusb device task
     led_blinking_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/dynamic_configuration/src/main.c b/examples/device/dynamic_configuration/src/main.c
index 90794e979a..578f01d8c5 100644
--- a/examples/device/dynamic_configuration/src/main.c
+++ b/examples/device/dynamic_configuration/src/main.c
@@ -66,8 +66,6 @@ int main(void)
     cdc_task();
     midi_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_composite/src/main.c b/examples/device/hid_composite/src/main.c
index 4edb045c21..8d0e6becef 100644
--- a/examples/device/hid_composite/src/main.c
+++ b/examples/device/hid_composite/src/main.c
@@ -67,8 +67,6 @@ int main(void)
 
     hid_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_generic_inout/src/main.c b/examples/device/hid_generic_inout/src/main.c
index 6649b49b51..5db8f5581c 100644
--- a/examples/device/hid_generic_inout/src/main.c
+++ b/examples/device/hid_generic_inout/src/main.c
@@ -88,8 +88,6 @@ int main(void)
     tud_task(); // tinyusb device task
     led_blinking_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_multiple_interface/src/main.c b/examples/device/hid_multiple_interface/src/main.c
index 29ba743984..72240b208b 100644
--- a/examples/device/hid_multiple_interface/src/main.c
+++ b/examples/device/hid_multiple_interface/src/main.c
@@ -71,8 +71,6 @@ int main(void)
 
     hid_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/midi_test/src/main.c b/examples/device/midi_test/src/main.c
index 66fa720631..2c3e9d954e 100644
--- a/examples/device/midi_test/src/main.c
+++ b/examples/device/midi_test/src/main.c
@@ -71,9 +71,6 @@ int main(void)
     led_blinking_task();
     midi_task();
   }
-
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/msc_dual_lun/src/main.c b/examples/device/msc_dual_lun/src/main.c
index 0a72849399..c7f6de7bf2 100644
--- a/examples/device/msc_dual_lun/src/main.c
+++ b/examples/device/msc_dual_lun/src/main.c
@@ -62,8 +62,6 @@ int main(void)
     tud_task(); // tinyusb device task
     led_blinking_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/uac2_headset/src/main.c b/examples/device/uac2_headset/src/main.c
index bafd40d347..19a3f7bae2 100644
--- a/examples/device/uac2_headset/src/main.c
+++ b/examples/device/uac2_headset/src/main.c
@@ -113,8 +113,6 @@ int main(void)
     audio_task();
     led_blinking_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/uac2_headset/src/usb_descriptors.h b/examples/device/uac2_headset/src/usb_descriptors.h
index 5525c916a1..457e698824 100644
--- a/examples/device/uac2_headset/src/usb_descriptors.h
+++ b/examples/device/uac2_headset/src/usb_descriptors.h
@@ -114,7 +114,7 @@ enum
     /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
     TUD_AUDIO_DESC_TYPE_I_FORMAT(CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_RX),\
     /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ADAPTIVE | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX), /*_interval*/ 0x01),\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ADAPTIVE | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX), /*_interval*/ 0x01),\
     /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
     TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_MILLISEC, /*_lockdelay*/ 0x0001),\
     /* Interface 1, Alternate 2 - alternate interface for data streaming */\
@@ -124,7 +124,7 @@ enum
     /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
     TUD_AUDIO_DESC_TYPE_I_FORMAT(CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_RX),\
     /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ADAPTIVE | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX), /*_interval*/ 0x01),\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ADAPTIVE | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX), /*_interval*/ 0x01),\
     /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
     TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_MILLISEC, /*_lockdelay*/ 0x0001),\
     /* Standard AS Interface Descriptor(4.9.1) */\
@@ -138,7 +138,7 @@ enum
     /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
     TUD_AUDIO_DESC_TYPE_I_FORMAT(CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_TX),\
     /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX), /*_interval*/ 0x01),\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX), /*_interval*/ 0x01),\
     /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
     TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED, /*_lockdelay*/ 0x0000),\
     /* Interface 2, Alternate 2 - alternate interface for data streaming */\
@@ -148,7 +148,7 @@ enum
     /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
     TUD_AUDIO_DESC_TYPE_I_FORMAT(CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_TX),\
     /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX), /*_interval*/ 0x01),\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX), /*_interval*/ 0x01),\
     /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
     TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED, /*_lockdelay*/ 0x0000)
 
diff --git a/examples/device/usbtmc/src/main.c b/examples/device/usbtmc/src/main.c
index da7f0418a1..2bba336f1e 100644
--- a/examples/device/usbtmc/src/main.c
+++ b/examples/device/usbtmc/src/main.c
@@ -63,8 +63,6 @@ int main(void)
     led_blinking_task();
     usbtmc_app_task_iter();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/usbtmc/src/usbtmc_app.c b/examples/device/usbtmc/src/usbtmc_app.c
index 503ee3071d..72989b4fe3 100644
--- a/examples/device/usbtmc/src/usbtmc_app.c
+++ b/examples/device/usbtmc/src/usbtmc_app.c
@@ -88,14 +88,6 @@ static size_t buffer_tx_ix; // for transmitting using multiple transfers
 static uint8_t buffer[225]; // A few packets long should be enough.
 
 
-static usbtmc_msg_dev_dep_msg_in_header_t rspMsg = {
-    .bmTransferAttributes =
-    {
-      .EOM = 1,
-      .UsingTermChar = 0
-    }
-};
-
 void tud_usbtmc_open_cb(uint8_t interface_id)
 {
   (void)interface_id;
@@ -148,12 +140,14 @@ bool tud_usbtmc_msg_data_cb(void *data, size_t len, bool transfer_complete)
   queryState = transfer_complete;
   idnQuery = 0;
 
-  if ( transfer_complete && (len >= 4) && (!strncmp("*idn?", data, 4) || !strncmp("*IDN?", data, 4)) )
+  if ( transfer_complete && (len >= 4) &&
+       (!strncmp("*idn?", data, 4) || !strncmp("*IDN?", data, 4)) )
   {
     idnQuery = 1;
   }
 
-  if ( transfer_complete && (!strncmp("delay ", data, 5) || !strncmp("DELAY ", data, 5)) )
+  if ( transfer_complete &&
+       (!strncmp("delay ", data, 5) || !strncmp("DELAY ", data, 5)) )
   {
     queryState = 0;
     int d = atoi((char*)data + 5);
@@ -185,9 +179,6 @@ static unsigned int msgReqLen;
 
 bool tud_usbtmc_msgBulkIn_request_cb(usbtmc_msg_request_dev_dep_in const * request)
 {
-  rspMsg.header.MsgID = request->header.MsgID,
-  rspMsg.header.bTag = request->header.bTag,
-  rspMsg.header.bTagInverse = request->header.bTagInverse;
   msgReqLen = request->TransferSize;
 
 #ifdef xDEBUG
@@ -251,7 +242,6 @@ void usbtmc_app_task_iter(void) {
     break;
   default:
     TU_ASSERT(false,);
-    return;
   }
 }
 
diff --git a/examples/device/video_capture/src/main.c b/examples/device/video_capture/src/main.c
index 08db1b00f3..5654e0b61e 100644
--- a/examples/device/video_capture/src/main.c
+++ b/examples/device/video_capture/src/main.c
@@ -66,8 +66,6 @@ int main(void)
 
     video_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/webusb_serial/src/main.c b/examples/device/webusb_serial/src/main.c
index 24456f9f35..838d86381a 100644
--- a/examples/device/webusb_serial/src/main.c
+++ b/examples/device/webusb_serial/src/main.c
@@ -103,8 +103,6 @@ int main(void)
     webserial_task();
     led_blinking_task();
   }
-
-  return 0;
 }
 
 // send characters to both CDC and WebUSB
diff --git a/examples/host/cdc_msc_hid/src/main.c b/examples/host/cdc_msc_hid/src/main.c
index 23312296f0..1f4acb822f 100644
--- a/examples/host/cdc_msc_hid/src/main.c
+++ b/examples/host/cdc_msc_hid/src/main.c
@@ -57,8 +57,6 @@ int main(void)
     cdc_app_task();
     hid_app_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/host/hid_controller/src/main.c b/examples/host/hid_controller/src/main.c
index 3380e92466..4dcc92587d 100644
--- a/examples/host/hid_controller/src/main.c
+++ b/examples/host/hid_controller/src/main.c
@@ -68,8 +68,6 @@ int main(void)
     hid_app_task();
 #endif
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+
diff --git a/src/class/usbtmc/usbtmc_device.c b/src/class/usbtmc/usbtmc_device.c
index 8dbda14c51..4e320a7785 100644
--- a/src/class/usbtmc/usbtmc_device.c
+++ b/src/class/usbtmc/usbtmc_device.c
@@ -154,7 +154,10 @@ TU_VERIFY_STATIC(USBTMCD_BUFFER_SIZE >= 32u,"USBTMC dev buffer size too small");
 static bool handle_devMsgOutStart(uint8_t rhport, void *data, size_t len);
 static bool handle_devMsgOut(uint8_t rhport, void *data, size_t len, size_t packetLen);
 
+#ifndef NDEBUG
 tu_static uint8_t termChar;
+#endif
+
 tu_static uint8_t termCharRequested = false;
 
 #if OSAL_MUTEX_REQUIRED
@@ -442,7 +445,10 @@ static bool handle_devMsgIn(void *data, size_t len)
   usbtmc_state.transfer_size_sent = 0u;
 
   termCharRequested = msg->bmTransferAttributes.TermCharEnabled;
+
+#ifndef NDEBUG
   termChar = msg->TermChar;
+#endif
 
   if(termCharRequested)
     TU_VERIFY(usbtmc_state.capabilities->bmDevCapabilities.canEndBulkInOnTermChar);
@@ -511,6 +517,7 @@ bool usbtmcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint
       return true;
 
     case STATE_ABORTING_BULK_OUT:
+      // Should be stalled by now, shouldn't have received a packet.
       return false;
 
     case STATE_TX_REQUESTED:
diff --git a/src/class/video/video.h b/src/class/video/video.h
index e8227ea606..c0088c4f69 100644
--- a/src/class/video/video.h
+++ b/src/class/video/video.h
@@ -549,7 +549,7 @@ TU_VERIFY_STATIC( sizeof(video_probe_and_commit_control_t) == 48, "size is not c
 
 /* 3.10.1.1 */
 #define TUD_VIDEO_DESC_EP_ISO(_ep, _epsize, _ep_interval) \
-  7, TUSB_DESC_ENDPOINT, _ep, TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS,\
+  7, TUSB_DESC_ENDPOINT, _ep, (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS),\
   U16_TO_U8S_LE(_epsize), _ep_interval
 
 /* 3.10.1.2 */
diff --git a/src/common/tusb_compiler.h b/src/common/tusb_compiler.h
index 1057d7ca30..713bbb8d49 100644
--- a/src/common/tusb_compiler.h
+++ b/src/common/tusb_compiler.h
@@ -196,7 +196,7 @@
   #define TU_ATTR_DEPRECATED(mess)      __attribute__ ((deprecated(mess))) // warn if function with this attribute is used
   #define TU_ATTR_UNUSED                __attribute__ ((unused))           // Function/Variable is meant to be possibly unused
   #define TU_ATTR_USED                  __attribute__ ((used))             // Function/Variable is meant to be used
-  #define TU_ATTR_FALLTHROUGH           __attribute__((fallthrough))
+  #define TU_ATTR_FALLTHROUGH           do {} while (0)  /* fallthrough */
 
   #define TU_ATTR_PACKED_BEGIN
   #define TU_ATTR_PACKED_END
diff --git a/src/device/usbd.h b/src/device/usbd.h
index ad19d1045b..255e5a844d 100644
--- a/src/device/usbd.h
+++ b/src/device/usbd.h
@@ -420,7 +420,7 @@ TU_ATTR_WEAK bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb
 /* Standard AS Isochronous Feedback Endpoint Descriptor(4.10.2.1) */
 #define TUD_AUDIO_DESC_STD_AS_ISO_FB_EP_LEN 7
 #define TUD_AUDIO_DESC_STD_AS_ISO_FB_EP(_ep, _interval) \
-  TUD_AUDIO_DESC_STD_AS_ISO_FB_EP_LEN, TUSB_DESC_ENDPOINT, _ep, (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_NO_SYNC | TUSB_ISO_EP_ATT_EXPLICIT_FB), U16_TO_U8S_LE(4), _interval
+  TUD_AUDIO_DESC_STD_AS_ISO_FB_EP_LEN, TUSB_DESC_ENDPOINT, _ep, (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_NO_SYNC | TUSB_ISO_EP_ATT_EXPLICIT_FB), U16_TO_U8S_LE(4), _interval
 
 // AUDIO simple descriptor (UAC2) for 1 microphone input
 // - 1 Input Terminal, 1 Feature Unit (Mute and Volume Control), 1 Output Terminal, 1 Clock Source
@@ -467,7 +467,7 @@ TU_ATTR_WEAK bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb
   /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
   TUD_AUDIO_DESC_TYPE_I_FORMAT(_nBytesPerSample, _nBitsUsedPerSample),\
   /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ TUD_OPT_HIGH_SPEED ? 0x04 : 0x01),\
+  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ TUD_OPT_HIGH_SPEED ? 0x04 : 0x01),\
   /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
   TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED, /*_lockdelay*/ 0x0000)
 
@@ -516,7 +516,7 @@ TU_ATTR_WEAK bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb
   /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
   TUD_AUDIO_DESC_TYPE_I_FORMAT(_nBytesPerSample, _nBitsUsedPerSample),\
   /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ TUD_OPT_HIGH_SPEED ? 0x04 : 0x01),\
+  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ TUD_OPT_HIGH_SPEED ? 0x04 : 0x01),\
   /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
   TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED, /*_lockdelay*/ 0x0000)
 
@@ -564,7 +564,7 @@ TU_ATTR_WEAK bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb
   /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
   TUD_AUDIO_DESC_TYPE_I_FORMAT(_nBytesPerSample, _nBitsUsedPerSample),\
   /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
-  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ TUD_OPT_HIGH_SPEED ? 0x04 : 0x01),\
+  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ TUD_OPT_HIGH_SPEED ? 0x04 : 0x01),\
   /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
   TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED, /*_lockdelay*/ 0x0000),\
   /* Standard AS Isochronous Feedback Endpoint Descriptor(4.10.2.1) */\
diff --git a/src/host/usbh.c b/src/host/usbh.c
index aeab681e9e..9ccbe75579 100644
--- a/src/host/usbh.c
+++ b/src/host/usbh.c
@@ -434,7 +434,7 @@ void tuh_task_ext(uint32_t timeout_ms, bool in_isr)
         {
           // device 0 only has control endpoint
           TU_ASSERT(epnum == 0, );
-          usbh_control_xfer_cb(event.dev_addr, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
+          usbh_control_xfer_cb(event.dev_addr, ep_addr, (xfer_result_t) event.xfer_complete.result, event.xfer_complete.len);
         }
         else
         {
@@ -446,14 +446,14 @@ void tuh_task_ext(uint32_t timeout_ms, bool in_isr)
 
           if ( 0 == epnum )
           {
-            usbh_control_xfer_cb(event.dev_addr, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
+            usbh_control_xfer_cb(event.dev_addr, ep_addr, (xfer_result_t) event.xfer_complete.result, event.xfer_complete.len);
           }else
           {
             uint8_t drv_id = dev->ep2drv[epnum][ep_dir];
             if(drv_id < USBH_CLASS_DRIVER_COUNT)
             {
               TU_LOG_USBH("%s xfer callback\r\n", usbh_class_drivers[drv_id].name);
-              usbh_class_drivers[drv_id].xfer_cb(event.dev_addr, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
+              usbh_class_drivers[drv_id].xfer_cb(event.dev_addr, ep_addr, (xfer_result_t) event.xfer_complete.result, event.xfer_complete.len);
             }
             else
             {
diff --git a/src/portable/raspberrypi/rp2040/dcd_rp2040.c b/src/portable/raspberrypi/rp2040/dcd_rp2040.c
index 4af8c2d714..500a5373fe 100644
--- a/src/portable/raspberrypi/rp2040/dcd_rp2040.c
+++ b/src/portable/raspberrypi/rp2040/dcd_rp2040.c
@@ -199,7 +199,7 @@ static void __tusb_irq_path_func(hw_handle_buff_status)(void)
             usb_hw_clear->buf_status = bit;
 
             // IN transfer for even i, OUT transfer for odd i
-            struct hw_endpoint *ep = hw_endpoint_get_by_num(i >> 1u, !(i & 1u));
+            struct hw_endpoint *ep = hw_endpoint_get_by_num(i >> 1u, (i & 1u) ? TUSB_DIR_OUT : TUSB_DIR_IN);
 
             // Continue xfer
             bool done = hw_endpoint_xfer_continue(ep);
diff --git a/src/portable/raspberrypi/rp2040/hcd_rp2040.c b/src/portable/raspberrypi/rp2040/hcd_rp2040.c
index 28abd79395..661255cf6b 100644
--- a/src/portable/raspberrypi/rp2040/hcd_rp2040.c
+++ b/src/portable/raspberrypi/rp2040/hcd_rp2040.c
@@ -446,7 +446,7 @@ tusb_speed_t hcd_port_speed_get(uint8_t rhport)
       return TUSB_SPEED_FULL;
     default:
       panic("Invalid speed\n");
-      return TUSB_SPEED_INVALID;
+      // return TUSB_SPEED_INVALID;
   }
 }
 
@@ -613,7 +613,7 @@ bool hcd_edpt_clear_stall(uint8_t dev_addr, uint8_t ep_addr)
   (void) ep_addr;
 
   panic("hcd_clear_stall");
-  return true;
+  // return true;
 }
 
 #endif
diff --git a/src/portable/raspberrypi/rp2040/rp2040_usb.c b/src/portable/raspberrypi/rp2040/rp2040_usb.c
index df05697fee..cf37cba075 100644
--- a/src/portable/raspberrypi/rp2040/rp2040_usb.c
+++ b/src/portable/raspberrypi/rp2040/rp2040_usb.c
@@ -68,15 +68,19 @@ void rp2040_usb_init(void)
   reset_block(RESETS_RESET_USBCTRL_BITS);
   unreset_block_wait(RESETS_RESET_USBCTRL_BITS);
 
+#ifdef __GNUC__
   // Clear any previous state just in case
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Warray-bounds"
 #if __GNUC__ > 6
 #pragma GCC diagnostic ignored "-Wstringop-overflow"
+#endif
 #endif
   memset(usb_hw, 0, sizeof(*usb_hw));
   memset(usb_dpram, 0, sizeof(*usb_dpram));
+#ifdef __GNUC__
 #pragma GCC diagnostic pop
+#endif
 
   // Mux the controller to the onboard usb phy
   usb_hw->muxing = USB_USB_MUXING_TO_PHY_BITS | USB_USB_MUXING_SOFTCON_BITS;
diff --git a/src/portable/raspberrypi/rp2040/rp2040_usb.h b/src/portable/raspberrypi/rp2040/rp2040_usb.h
index 9f8e58d425..5d3d792cb6 100644
--- a/src/portable/raspberrypi/rp2040/rp2040_usb.h
+++ b/src/portable/raspberrypi/rp2040/rp2040_usb.h
@@ -36,8 +36,8 @@
 #define __tusb_irq_path_func(x) x
 #endif
 
-#define usb_hw_set hw_set_alias(usb_hw)
-#define usb_hw_clear hw_clear_alias(usb_hw)
+#define usb_hw_set    ((usb_hw_t *) hw_set_alias(usb_hw))
+#define usb_hw_clear  ((usb_hw_t *) hw_clear_alias(usb_hw))
 
 #define pico_info(...)  TU_LOG(2, __VA_ARGS__)
 #define pico_trace(...) TU_LOG(3, __VA_ARGS__)
@@ -119,17 +119,17 @@ TU_ATTR_ALWAYS_INLINE static inline uint32_t _hw_endpoint_buffer_control_get_val
 
 TU_ATTR_ALWAYS_INLINE static inline void _hw_endpoint_buffer_control_set_value32 (struct hw_endpoint *ep, uint32_t value)
 {
-  return _hw_endpoint_buffer_control_update32(ep, 0, value);
+  _hw_endpoint_buffer_control_update32(ep, 0, value);
 }
 
 TU_ATTR_ALWAYS_INLINE static inline void _hw_endpoint_buffer_control_set_mask32 (struct hw_endpoint *ep, uint32_t value)
 {
-  return _hw_endpoint_buffer_control_update32(ep, ~value, value);
+  _hw_endpoint_buffer_control_update32(ep, ~value, value);
 }
 
 TU_ATTR_ALWAYS_INLINE static inline void _hw_endpoint_buffer_control_clear_mask32 (struct hw_endpoint *ep, uint32_t value)
 {
-  return _hw_endpoint_buffer_control_update32(ep, ~value, 0);
+  _hw_endpoint_buffer_control_update32(ep, ~value, 0);
 }
 
 static inline uintptr_t hw_data_offset (uint8_t *buf)