diff --git a/cores/arduino/PluggableUSB.cpp b/cores/arduino/PluggableUSB.cpp
index b27146b..2c7221d 100644
--- a/cores/arduino/PluggableUSB.cpp
+++ b/cores/arduino/PluggableUSB.cpp
@@ -25,21 +25,21 @@
 
 #define MAX_MODULES	6
 
-static u8 lastIf = CDC_ACM_INTERFACE + CDC_INTERFACE_COUNT;
-static u8 lastEp = CDC_FIRST_ENDPOINT + CDC_ENPOINT_COUNT;
+static uint8_t lastIf = CDC_ACM_INTERFACE + CDC_INTERFACE_COUNT;
+static uint8_t lastEp = CDC_FIRST_ENDPOINT + CDC_ENPOINT_COUNT;
 
-extern u8 _initEndpoints[];
+extern uint8_t _initEndpoints[];
 
 //PUSBCallbacks cbs[MAX_MODULES];
-static u8 modules_count = 0;
+static uint8_t modules_count = 0;
 
 static PUSBListNode* rootNode = NULL;
 
-int PluggableUSB_::getInterface(u8* interfaceNum)
+int PluggableUSB_::getInterface(uint8_t* interfaceNum)
 {
 	int ret = 0;
 	PUSBListNode* node = rootNode;
-	for (u8 i=0; i<modules_count; i++) {
+	for (uint8_t i=0; i<modules_count; i++) {
 		ret = node->getInterface(interfaceNum);
 		node = node->next;
 	}
@@ -50,18 +50,18 @@ int PluggableUSB_::getDescriptor(int8_t t)
 {
 	int ret = 0;
 	PUSBListNode* node = rootNode;
-	for (u8 i=0; i<modules_count && ret == 0; i++) {
+	for (uint8_t i=0; i<modules_count && ret == 0; i++) {
 		ret = node->getDescriptor(t);
 		node = node->next;
 	}
 	return ret;
 }
 
-bool PluggableUSB_::setup(USBSetup& setup, u8 j)
+bool PluggableUSB_::setup(USBSetup& setup, uint8_t j)
 {
 	bool ret = false;
 	PUSBListNode* node = rootNode;
-	for (u8 i=0; i<modules_count && ret == false; i++) {
+	for (uint8_t i=0; i<modules_count && ret == false; i++) {
 		ret = node->setup(setup, j);
 		node = node->next;
 	}
diff --git a/cores/arduino/PluggableUSB.h b/cores/arduino/PluggableUSB.h
index 275a444..d4a1096 100644
--- a/cores/arduino/PluggableUSB.h
+++ b/cores/arduino/PluggableUSB.h
@@ -28,8 +28,8 @@
 class PUSBListNode {
 public:
   PUSBListNode() { }
-  bool (*setup)(USBSetup& setup, u8 i);
-  int (*getInterface)(u8* interfaceNum);
+  bool (*setup)(USBSetup& setup, uint8_t i);
+  int (*getInterface)(uint8_t* interfaceNum);
   int (*getDescriptor)(int8_t t);
   int8_t numEndpoints;
   int8_t numInterfaces;
@@ -51,9 +51,9 @@ public:
 class PluggableUSB_ {
 public:
   static bool plug(PUSBListNode *node);
-  static int getInterface(u8* interfaceNum);
+  static int getInterface(uint8_t* interfaceNum);
   static int getDescriptor(int8_t t);
-  static bool setup(USBSetup& setup, u8 i);
+  static bool setup(USBSetup& setup, uint8_t i);
 };
 
 extern PluggableUSB_ PluggableUSB;
diff --git a/libraries/HID/HID.cpp b/libraries/HID/HID.cpp
index 7e4d991..e36601f 100644
--- a/libraries/HID/HID.cpp
+++ b/libraries/HID/HID.cpp
@@ -83,7 +83,7 @@ void HID_::AppendDescriptor(HIDDescriptorListNode *node)
 	sizeof_hidReportDescriptor += (uint16_t)node->length;
 }
 
-void HID_::SendReport(u8 id, const void* data, int len)
+void HID_::SendReport(uint8_t id, const void* data, int len)
 {
 	USB_Send(HID.endpoint(), &id, 1);
 	USB_Send(HID.endpoint() | TRANSFER_RELEASE,data,len);