diff --git a/Usb.cpp b/Usb.cpp
index a94ff8bb..a8096cad 100644
--- a/Usb.cpp
+++ b/Usb.cpp
@@ -108,7 +108,8 @@ uint8_t USB::SetAddress(uint8_t addr, uint8_t ep, EpInfo **ppep, uint16_t &nak_l
 		return USB_ERROR_EP_NOT_FOUND_IN_TBL;
 
 	nak_limit = (0x0001UL << ( ( (*ppep)->bmNakPower > USB_NAK_MAX_POWER ) ? USB_NAK_MAX_POWER : (*ppep)->bmNakPower) );
-	nak_limit--;  
+	nak_limit--;
+	  
 /*
   USBTRACE2("\r\nAddress: ", addr);
   USBTRACE2(" EP: ", ep);
diff --git a/Usb.h b/Usb.h
index c0953f3b..341c1368 100644
--- a/Usb.h
+++ b/Usb.h
@@ -47,16 +47,8 @@ e-mail   :  support@circuitsathome.com
 
 /* shield pins. First parameter - SS pin, second parameter - INT pin */
 
-#if defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
-#define BOARD_TEENSY_PLUS_PLUS
-#endif
-
 #ifdef BOARD_BLACK_WIDDOW
 typedef MAX3421e<P6, P3>		MAX3421E;		// Black Widow
-#elif defined(BOARD_TEENSY_PLUS_PLUS)
-typedef MAX3421e<P9, P8>        MAX3421E;       // Teensy++ 2.0 & 1.0
-#elif defined(BOARD_MEGA_ADK)
-typedef MAX3421e<P53, P54>              MAX3421E;               // Arduino Mega ADK
 #else
 typedef MAX3421e<P10, P9>		MAX3421E;		// Official Arduinos (UNO, Duemilanove, Mega, 2560
 #endif
@@ -280,4 +272,4 @@ inline uint8_t USB::setConf( uint8_t addr, uint8_t ep, uint8_t conf_value )
 
 #endif // defined(USB_METHODS_INLINE)
 
-#endif //_usb_h_
+#endif //_usb_h_
\ No newline at end of file
diff --git a/adk.cpp b/adk.cpp
index 1304992a..e846d611 100644
--- a/adk.cpp
+++ b/adk.cpp
@@ -48,11 +48,12 @@ ADK::ADK(USB *p,  const char* manufacturer,
 	for(uint8_t i=0; i<ADK_MAX_ENDPOINTS; i++) {
 		epInfo[i].epAddr		= 0;
 		epInfo[i].maxPktSize	= (i) ? 0 : 8;
-		epInfo[i].epAttribs		= 0;
-		epInfo[i].bmNakPower	= (i) ? USB_NAK_NOWAIT : USB_NAK_MAX_POWER;
-		//epInfo[i].bmNakPower = USB_NAK_MAX_POWER;
+		epInfo[i].epAttribs		= ( 0xfc & ( USB_NAK_MAX_POWER<<2 ));
   }//for(uint8_t i=0; i<ADK_MAX_ENDPOINTS; i++...
   
+  //set bulk-IN EP naklimit to 1 
+  epInfo[epDataInIndex].epAttribs = ( 0xfc & ( USB_NAK_NOWAIT<<2 ));
+  
   // register in USB subsystem
 	if (pUsb) {
 		pUsb->RegisterDeviceClass(this);  //set devConfig[] entry
@@ -156,16 +157,7 @@ uint8_t ADK::Init(uint8_t parent, uint8_t port, bool lowspeed)
 
 		          for (uint8_t i=0; i<num_of_conf; i++) {
 			          ConfigDescParser<0, 0, 0, 0> confDescrParser(this);
-			          delay(1);
 	    			    rcode = pUsb->getConfDescr(bAddress, 0, i, &confDescrParser);
-#if defined(XOOM)
-                //added by Jaylen Scott Vanorden
-                if( rcode ) {
-                  USBTRACE2("\r\nGot 1st bad code for config: ", rcode);
-                  // Try once more
-                  rcode = pUsb->getConfDescr(bAddress, 0, i, &confDescrParser);
-                }
-#endif	    			    
                 if( rcode ) {
                   goto FailGetConfDescr;
                 }
@@ -181,7 +173,9 @@ uint8_t ADK::Init(uint8_t parent, uint8_t port, bool lowspeed)
 		              goto FailSetDevTblEntry;
 		            }
 		          }
-	
+		
+		
+		
               // Set Configuration Value
 	            rcode = pUsb->setConf(bAddress, 0, bConfNum);
 	            if( rcode ){ 
@@ -207,22 +201,11 @@ uint8_t ADK::Init(uint8_t parent, uint8_t port, bool lowspeed)
               return 0; //successful configuration
     }//if( buf->idVendor == ADK_VID...
 		
-		//delay(20);  //testing compatibility w/Motorola Xoom
-		
 		//probe device - get accessory protocol revision
 		{
 		  uint16_t adkproto = -1;
-		  delay(1);
 		  rcode = getProto((uint8_t*)&adkproto );
-#if defined(XOOM)
-          //added by Jaylen Scott Vanorden
-          if( rcode ) {
-            USBTRACE2("\r\nGot 1st bad code for proto: ", rcode);
-            // Try once more
-            rcode = getProto((uint8_t*)&adkproto );
-          }          
-#endif
-      if( rcode ){		  
+		  if( rcode ){
 		    goto FailGetProto; //init fails
 		  }
 		  USBTRACE2("\r\nADK protocol rev. ", adkproto );
diff --git a/adk.h b/adk.h
index 8084decb..024b013b 100644
--- a/adk.h
+++ b/adk.h
@@ -44,10 +44,6 @@ e-mail   :  support@circuitsathome.com
 #define ADK_PID   0x2D00
 #define ADB_PID   0x2D01
 
-#define XOOM  //enables repeating getProto() and getConf() attempts
-              //necessary for slow devices such as Motorola XOOM
-              //defined by default, can be commented out to save memory
-
 /* requests */
 
 #define ADK_GETPROTO      51  //check USB accessory protocol version
@@ -109,7 +105,7 @@ public:
                   const char* uri,
                   const char* serial);
 
-	// Methods for receiving and sending data
+	// Methods for recieving and sending data
 	uint8_t RcvData(uint16_t *nbytesptr, uint8_t *dataptr);
 	uint8_t SndData(uint16_t nbytes, uint8_t *dataptr);
 
diff --git a/avrpins.h b/avrpins.h
index eb999a98..99e10776 100644
--- a/avrpins.h
+++ b/avrpins.h
@@ -20,9 +20,6 @@ e-mail   :  support@circuitsathome.com
 #ifndef _avrpins_h_
 #define _avrpins_h_
 
-/* Uncomment the following if you have Arduino Mega ADK board with MAX3421e built-in */
-//#define BOARD_MEGA_ADK
-
 #include <avr/io.h>
 
 #ifdef PORTA
@@ -468,7 +465,6 @@ template<typename Tp_pin, typename Tc_bit>
 #define P51 Pb2
 #define P52 Pb1
 #define P53 Pb0
-#define P54 Pj2
 
 #endif  //"Mega" pin numbers
 
diff --git a/cdcacm.cpp b/cdcacm.cpp
index df013fbc..9f9f6193 100644
--- a/cdcacm.cpp
+++ b/cdcacm.cpp
@@ -28,18 +28,20 @@ ACM::ACM(USB *p, CDCAsyncOper *pasync) :
 	bPollEnable(false),	
 	bControlIface(0),	
 	bDataIface(0),		
-	bNumEP(1)			
+	bNumEP(1),
+	ready(false)			
 {
 	for(uint8_t i=0; i<ACM_MAX_ENDPOINTS; i++)
 	{
 		epInfo[i].epAddr		= 0;
 		epInfo[i].maxPktSize	= (i) ? 0 : 8;
 		epInfo[i].epAttribs		= 0;
-		//epInfo[i].bmNakPower = USB_NAK_NOWAIT;
-    epInfo[i].bmNakPower = USB_NAK_MAX_POWER;
+		epInfo[i].bmNakPower = USB_NAK_NOWAIT;
+    //epInfo[i].bmNakPower = USB_NAK_MAX_POWER;
     
-		//if (!i)
-			epInfo[i].bmNakPower	= USB_NAK_MAX_POWER;
+		if (!i)
+			epInfo[i].bmNakPower	= USB_NAK_MAX_POWER; 
+			
 	}
 	if (pUsb)
 		pUsb->RegisterDeviceClass(this);
@@ -172,6 +174,7 @@ uint8_t ACM::Init(uint8_t parent, uint8_t port, bool lowspeed)
 		goto FailOnInit;
 
 	USBTRACE("ACM configured\r\n");
+	ready = true;
 
 	//bPollEnable = true;
 
@@ -226,7 +229,7 @@ void ACM::EndpointXtract(uint8_t conf, uint8_t iface, uint8_t alt, uint8_t proto
 	// Fill in the endpoint info structure
 	epInfo[index].epAddr		= (pep->bEndpointAddress & 0x0F);
 	epInfo[index].maxPktSize	= (uint8_t)pep->wMaxPacketSize;
-	epInfo[index].epAttribs		= 0;
+	//epInfo[index].epAttribs		= 0;
 
 	bNumEP ++;
 
@@ -244,6 +247,7 @@ uint8_t ACM::Release()
 	bAddress			= 0;
 	qNextPollTime		= 0;
 	bPollEnable			= false;
+	ready = false;
 	return 0;
 }
 
@@ -254,7 +258,7 @@ uint8_t ACM::Poll()
 	if (!bPollEnable)
 		return 0;
 
-	uint32_t	time_now = millis();
+	//uint32_t	time_now = millis();
 
 	//if (qNextPollTime <= time_now)
 	//{
diff --git a/cdcacm.h b/cdcacm.h
index b315787d..062ad696 100644
--- a/cdcacm.h
+++ b/cdcacm.h
@@ -154,6 +154,7 @@ protected:
 	uint8_t		bNumEP;					// total number of EP in the configuration
 	uint32_t	qNextPollTime;			// next poll time
 	bool		bPollEnable;			// poll enable flag
+	bool  ready;      //device ready indicator        
 
 	EpInfo		epInfo[ACM_MAX_ENDPOINTS];
 
@@ -179,6 +180,7 @@ public:
 	virtual uint8_t Release();
 	virtual uint8_t Poll();
 	virtual uint8_t GetAddress() { return bAddress; };
+	virtual bool isReady() { return ready; };
 
 	// UsbConfigXtracter implementation
 	virtual void EndpointXtract(uint8_t conf, uint8_t iface, uint8_t alt, uint8_t proto, const USB_ENDPOINT_DESCRIPTOR *ep);
diff --git a/cdcftdi.cpp b/cdcftdi.cpp
index 04fdca9a..4dbbc267 100644
--- a/cdcftdi.cpp
+++ b/cdcftdi.cpp
@@ -232,7 +232,7 @@ void FTDI::EndpointXtract(uint8_t conf, uint8_t iface, uint8_t alt, uint8_t prot
 	// Fill in the endpoint info structure
 	epInfo[index].epAddr		= (pep->bEndpointAddress & 0x0F);
 	epInfo[index].maxPktSize	= (uint8_t)pep->wMaxPacketSize;
-	epInfo[index].epAttribs		= 0;
+	//epInfo[index].epAttribs		= 0;
 
 	bNumEP ++;
 
diff --git a/cdcprolific.cpp b/cdcprolific.cpp
index 30694d43..23189d6e 100644
--- a/cdcprolific.cpp
+++ b/cdcprolific.cpp
@@ -17,8 +17,8 @@ e-mail   :  support@circuitsathome.com
 #include "cdcprolific.h"
 
 PL2303::PL2303(USB *p, CDCAsyncOper *pasync) :
-	ACM(p, pasync),
-	wPLType(0)
+	ACM(p, pasync)
+	//wPLType(0)
 {
 }
 
@@ -31,6 +31,7 @@ uint8_t PL2303::Init(uint8_t parent, uint8_t port, bool lowspeed)
 	UsbDevice	*p = NULL;
 	EpInfo		*oldep_ptr = NULL;
 	uint8_t		num_of_conf;	// number of configurations
+	enum pl2303_type pltype = unknown;
 
 	AddressPool	&addrPool = pUsb->GetAddressPool();
 
@@ -68,11 +69,24 @@ uint8_t PL2303::Init(uint8_t parent, uint8_t port, bool lowspeed)
 	if( rcode ) 
 		goto FailGetDevDescr;
 
-	if (((USB_DEVICE_DESCRIPTOR*)buf)->idVendor != PL_VID && ((USB_DEVICE_DESCRIPTOR*)buf)->idProduct != PL_PID )
+	if (((USB_DEVICE_DESCRIPTOR*)buf)->idVendor != PL_VID && ((USB_DEVICE_DESCRIPTOR*)buf)->idProduct != PL_PID ) {
 		return USB_DEV_CONFIG_ERROR_DEVICE_NOT_SUPPORTED;
-
-	// Save type of PL chip
-	wPLType = ((USB_DEVICE_DESCRIPTOR*)buf)->bcdDevice;
+	}
+	
+	/* determine chip variant */	
+		
+  if (((USB_DEVICE_DESCRIPTOR*)buf)->bDeviceClass == 0x02 ) {
+    pltype = type_0;
+  }
+	else if (((USB_DEVICE_DESCRIPTOR*)buf)->bMaxPacketSize0 == 0x40 ) { 
+		pltype = rev_HX;
+	}
+  else if (((USB_DEVICE_DESCRIPTOR*)buf)->bDeviceClass == 0x00) {
+    pltype = type_1;
+  }
+	else if (((USB_DEVICE_DESCRIPTOR*)buf)->bDeviceClass == 0xff) {
+		pltype = type_1;
+	}
 
 	// Allocate new address according to device class
 	bAddress = addrPool.AllocAddress(parent, false, port);
@@ -116,7 +130,7 @@ uint8_t PL2303::Init(uint8_t parent, uint8_t port, bool lowspeed)
 
 	USBTRACE2("NC:", num_of_conf);
 
-	for (uint8_t i=0; i<num_of_conf; i++)
+	for( uint8_t i=0; i<num_of_conf; i++ )
 	{
 		HexDumper<USBReadParser, uint16_t, uint16_t>		HexDump;
 		ConfigDescParser<0xFF, 0, 0, CP_MASK_COMPARE_CLASS>	confDescrParser(this);
@@ -128,11 +142,11 @@ uint8_t PL2303::Init(uint8_t parent, uint8_t port, bool lowspeed)
 			break;
 	} // for
 	
-	if (bNumEP < 2)
+	if ( bNumEP < 2 )
 		return USB_DEV_CONFIG_ERROR_DEVICE_NOT_SUPPORTED;
 
 	// Assign epInfo to epinfo pointer
-	rcode = pUsb->setEpInfoEntry(bAddress, bNumEP, epInfo);
+	rcode = pUsb->setEpInfoEntry( bAddress, bNumEP, epInfo );
 
 	USBTRACE2("Conf:", bConfNum);
 
@@ -142,6 +156,29 @@ uint8_t PL2303::Init(uint8_t parent, uint8_t port, bool lowspeed)
 	if (rcode)
 		goto FailSetConfDescr;
 
+#if defined(PL2303_COMPAT)
+	/* shamanic dance - sending Prolific init data as-is */
+	vendorRead( 0x84, 0x84, 0, buf );
+	vendorWrite( 0x04, 0x04, 0 );
+	vendorRead( 0x84, 0x84, 0, buf );
+	vendorRead( 0x83, 0x83, 0, buf );
+	vendorRead( 0x84, 0x84, 0, buf );
+	vendorWrite( 0x04, 0x04, 1 );
+	vendorRead( 0x84, 0x84, 0, buf);
+	vendorRead( 0x83, 0x83, 0, buf);
+	vendorWrite( 0, 0, 1 );
+	vendorWrite( 1, 0, 0 );
+	if ( pltype == rev_HX ) {
+		vendorWrite( 2, 0, 0x44 );
+		vendorWrite( 0x06, 0x06, 0 );   //from W7 init
+	}
+	else {
+		vendorWrite( 2, 0, 0x24 );
+	}
+	/* shamanic dance end */
+#endif	
+	
+  /* calling post-init callback */
 	rcode = pAsync->OnInit(this);
 
 	if (rcode)
@@ -149,7 +186,8 @@ uint8_t PL2303::Init(uint8_t parent, uint8_t port, bool lowspeed)
 
 	USBTRACE("PL configured\r\n");
 
-	bPollEnable = true;
+	//bPollEnable = true;
+	ready = true;
 	return 0;
 
 FailGetDevDescr:
diff --git a/cdcprolific.h b/cdcprolific.h
index b008ddd0..38e7d032 100644
--- a/cdcprolific.h
+++ b/cdcprolific.h
@@ -38,11 +38,11 @@ e-mail   :  support@circuitsathome.com
 #include "confdescparser.h"
 #include "cdcacm.h"
 
+//#define PL2303_COMPAT //uncomment it if you have compatibility problems
+
 #define PL_VID									0x067B
 #define PL_PID									( 0x2303 || 0x0609 )
 
-//#define PL_PID                    0x0609
-
 #define PROLIFIC_REV_H							0x0202
 #define PROLIFIC_REV_X							0x0300
 #define PROLIFIC_REV_HX_CHIP_D					0x0400
@@ -128,6 +128,7 @@ enum tXO_State
 enum pl2303_type 
 {
 	unknown,
+	type_0,
 	type_1,		/* don't know the difference between type 0 and */
 	rev_X,		/* type 1, until someone from prolific tells us... */
 	rev_HX,		/* HX version of the pl2303 chip */
@@ -137,9 +138,13 @@ enum pl2303_type
 
 #define PL_MAX_ENDPOINTS					4
 
+//class PL2303;
+
 class PL2303 : public ACM
 {
-	uint16_t	wPLType;				// Type of chip
+    
+	//uint16_t	wPLType;				// Type of chip
+  
 
 public:
 	PL2303(USB *pusb, CDCAsyncOper *pasync);
@@ -152,6 +157,23 @@ public:
 
 	//// UsbConfigXtracter implementation
 	//virtual void EndpointXtract(uint8_t conf, uint8_t iface, uint8_t alt, uint8_t proto, const USB_ENDPOINT_DESCRIPTOR *ep);
+
+private:
+    /* Prolific proprietary requests */
+    uint8_t vendorRead( uint8_t val_lo, uint8_t val_hi, uint16_t index, uint8_t* buf );
+    uint8_t vendorWrite( uint8_t val_lo, uint8_t val_hi, uint8_t index );  
 };
 
+/* vendor read request */
+inline uint8_t PL2303::vendorRead( uint8_t val_lo, uint8_t val_hi, uint16_t index, uint8_t* buf )
+{
+  return( pUsb->ctrlReq(bAddress, 0, VENDOR_READ_REQUEST_TYPE, VENDOR_READ_REQUEST, val_lo, val_hi, index, 1, 1, buf, NULL ));
+}
+
+/* vendor write request */
+inline uint8_t PL2303::vendorWrite( uint8_t val_lo, uint8_t val_hi, uint8_t index )
+{
+  return( pUsb->ctrlReq(bAddress, 0, VENDOR_WRITE_REQUEST_TYPE, VENDOR_WRITE_REQUEST, val_lo, val_hi, index, 0, 0, NULL, NULL ));
+}
+
 #endif // __CDCPROLIFIC_H__
\ No newline at end of file
diff --git a/confdescparser.h b/confdescparser.h
index 3d82f349..0c215227 100644
--- a/confdescparser.h
+++ b/confdescparser.h
@@ -110,7 +110,7 @@ bool ConfigDescParser<CLASS_ID, SUBCLASS_ID, PROTOCOL_ID, MASK>::ParseDescriptor
         dscrType		= *((uint8_t*)theBuffer.pValue + 1); 
 		stateParseDescr	= 2;
 	case 2:
-		// This is a sort of hack. Assuming that two bytes are already in the buffer 
+		// This is a sort of hack. Assuming that two bytes are allready in the buffer 
 		//	the pointer is positioned two bytes ahead in order for the rest of descriptor 
 		//	to be read right after the size and the type fields.
 		// This should be used carefuly. varBuffer should be used directly to handle data
diff --git a/examples/acm/acm_terminal/acm_terminal.pde b/examples/acm/acm_terminal/acm_terminal.pde
index ae2756d0..a60115c6 100644
--- a/examples/acm/acm_terminal/acm_terminal.pde
+++ b/examples/acm/acm_terminal/acm_terminal.pde
@@ -68,8 +68,7 @@ void loop()
 {
     Usb.Task();
   
-    if( Usb.getUsbTaskState() == USB_STATE_RUNNING )
-    {  
+    if( Acm.isReady()) {  
        uint8_t rcode;
        
        /* reading the keyboard */
diff --git a/examples/pl2303/pl2303_gps/pl2303_gps.pde b/examples/pl2303/pl2303_gps/pl2303_gps.pde
index 24585e0a..8cf26fd5 100644
--- a/examples/pl2303/pl2303_gps/pl2303_gps.pde
+++ b/examples/pl2303/pl2303_gps/pl2303_gps.pde
@@ -76,9 +76,8 @@ uint8_t  buf[64];    //serial buffer equals Max.packet size of bulk-IN endpoint
 uint16_t rcvd = 64;   
 
   Usb.Task();
-  
-    if( Usb.getUsbTaskState() == USB_STATE_RUNNING )
-    {  
+    
+    if( Pl.isReady()) {  
        /* reading the GPS */
        if( read_delay < millis() ){
        read_delay += READ_DELAY;  
diff --git a/examples/pl2303/pl2303_tinygps/pl2303_tinygps.pde b/examples/pl2303/pl2303_tinygps/pl2303_tinygps.pde
index 985f9d3d..85798192 100644
--- a/examples/pl2303/pl2303_tinygps/pl2303_tinygps.pde
+++ b/examples/pl2303/pl2303_tinygps/pl2303_tinygps.pde
@@ -95,7 +95,7 @@ void loop()
 {
   Usb.Task();
   
-  if( Usb.getUsbTaskState() == USB_STATE_RUNNING ) {
+  if( Pl.isReady()) {
   
     bool newdata = false;
     unsigned long start = millis();
@@ -210,7 +210,7 @@ bool feedgps()
             rcode = false;
             if( rcvd ) { //more than zero bytes received
               for( uint16_t i=0; i < rcvd; i++ ) {
-                if( gps.encode(buf[i])) { //feed a character to gps object
+                if( gps.encode((char)buf[i])) { //feed a character to gps object
                   rcode = true;
                 }//if( gps.encode(buf[i]...
               }//for( uint16_t i=0; i < rcvd; i++...              
diff --git a/usbhost.h b/usbhost.h
index a94b42e1..264b317a 100644
--- a/usbhost.h
+++ b/usbhost.h
@@ -87,12 +87,6 @@ MAX3421e< SS, INTR >::MAX3421e()
   spi::init();
   INTR::SetDirRead();
 
-#ifdef BOARD_MEGA_ADK  
-  /* For Mega ADK, which has Max3421e on-board, set MAX_RESET to Output mode, and pull Reset to HIGH */
-  DDRJ |= 0x04;
-  PORTJ |= 0x04;
-#endif
-
   /* MAX3421E - full-duplex SPI, level interrupt */
   regWr( rPINCTL,( bmFDUPSPI + bmINTLEVEL ));
 };