diff --git a/libraries/USBHost/src/Usb.cpp b/libraries/USBHost/src/Usb.cpp
index cdde1a670..de6d5ace9 100644
--- a/libraries/USBHost/src/Usb.cpp
+++ b/libraries/USBHost/src/Usb.cpp
@@ -143,7 +143,7 @@ uint32_t USBHost::ctrlReq(uint32_t addr, uint32_t ep, uint8_t bmReqType, uint8_t
 	if (rcode)
 	{
 		TRACE_USBHOST(printf("/!\\ USBHost::ctrlReq : EP0 allocation error: %lu\r\n", rcode);)
-		//USBTRACE2("\n\rUSBHost::ctrlReq : EP0 allocation error: ", rcode");
+		//USBTRACE2("\n\rUSBHost::ctrlReq : EP0 allocation error: ", rcode");
 		return rcode;
 	}
 
@@ -263,6 +263,7 @@ uint32_t USBHost::InTransfer(EpInfo *pep, uint32_t nak_limit, uint8_t *nbytesptr
             continue;
 		}
         if(rcode) {
+                uhd_freeze_pipe(pep->epAddr);
                 //printf(">>>>>>>> Problem! dispatchPkt %2.2x\r\n", rcode);
                 return(rcode);// break; //should be 0, indicating ACK. Else return error code.
         }
@@ -305,6 +306,7 @@ uint32_t USBHost::InTransfer(EpInfo *pep, uint32_t nak_limit, uint8_t *nbytesptr
             break;
 		} // if
 	} //while( 1 )
+	uhd_freeze_pipe(pep->epAddr);
 	return ( rcode);
 }
 
@@ -422,6 +424,16 @@ uint32_t USBHost::dispatchPkt(uint32_t token, uint32_t epAddr, uint32_t nak_limi
 			return 0;
 		}
 
+		//case hrNAK:
+		if((USB->HOST.HostPipe[epAddr].PINTFLAG.reg & USB_HOST_PINTFLAG_TRFAIL) ) {
+			USB->HOST.HostPipe[epAddr].PINTFLAG.reg = USB_HOST_PINTFLAG_TRFAIL;
+			nak_count++;
+			if(nak_limit && (nak_count == nak_limit)) {
+				rcode = USB_ERRORFLOW;
+				return (rcode);
+			}
+		}
+
 		//case hrNAK:
 		if( (usb_pipe_table[epAddr].HostDescBank[0].STATUS_BK.reg & USB_ERRORFLOW ) ) {
 			nak_count++;