XPROG_SelectedProtocol = SetMode_XPROG_Params.Protocol;
 
-       Endpoint_Write_Byte(CMD_XPROG_SETMODE);
-       Endpoint_Write_Byte((SetMode_XPROG_Params.Protocol != XPRG_PROTOCOL_JTAG) ? STATUS_CMD_OK : STATUS_CMD_FAILED);
+       Endpoint_Write_8(CMD_XPROG_SETMODE);
+       Endpoint_Write_8((SetMode_XPROG_Params.Protocol != XPRG_PROTOCOL_JTAG) ? STATUS_CMD_OK : STATUS_CMD_FAILED);
        Endpoint_ClearIN();
 }
 
  */
 void XPROGProtocol_Command(void)
 {
-       uint8_t XPROGCommand = Endpoint_Read_Byte();
+       uint8_t XPROGCommand = Endpoint_Read_8();
 
        switch (XPROGCommand)
        {
        else if (XPROG_SelectedProtocol == XPRG_PROTOCOL_TPI)
          NVMBusEnabled = TINYNVM_EnableTPI();
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_ENTER_PROGMODE);
-       Endpoint_Write_Byte(NVMBusEnabled ? XPRG_ERR_OK : XPRG_ERR_FAILED);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_ENTER_PROGMODE);
+       Endpoint_Write_8(NVMBusEnabled ? XPRG_ERR_OK : XPRG_ERR_FAILED);
        Endpoint_ClearIN();
 }
 
          TINYNVM_DisableTPI();
 
        #if defined(XCK_RESCUE_CLOCK_ENABLE) && defined(ENABLE_ISP_PROTOCOL)
+       /* If the XCK rescue clock option is enabled, we need to restart it once the 
+        * XPROG mode has been exited, since the XPROG protocol stops it after use. */
        ISPTarget_ConfigureRescueClock();
        #endif
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_LEAVE_PROGMODE);
-       Endpoint_Write_Byte(XPRG_ERR_OK);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_LEAVE_PROGMODE);
+       Endpoint_Write_8(XPRG_ERR_OK);
        Endpoint_ClearIN();
 }
 
                  ReturnStatus = XPRG_ERR_TIMEOUT;
        }
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_ERASE);
-       Endpoint_Write_Byte(ReturnStatus);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_ERASE);
+       Endpoint_Write_8(ReturnStatus);
        Endpoint_ClearIN();
 }
 
        WriteMemory_XPROG_Params.Length  = SwapEndian_16(WriteMemory_XPROG_Params.Length);
        Endpoint_Read_Stream_LE(&WriteMemory_XPROG_Params.ProgData, WriteMemory_XPROG_Params.Length, NULL);
 
+       // The driver will terminate transfers that are a round multiple of the endpoint bank in size with a ZLP, need
+       // to catch this and discard it before continuing on with packet processing to prevent communication issues
+       if (((sizeof(uint8_t) + sizeof(WriteMemory_XPROG_Params) - sizeof(WriteMemory_XPROG_Params.ProgData)) +
+           WriteMemory_XPROG_Params.Length) % AVRISP_DATA_EPSIZE == 0)
+       {
+               Endpoint_ClearOUT();
+               Endpoint_WaitUntilReady();
+       }
+       
        Endpoint_ClearOUT();
        Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPNUM);
        Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
                }
        }
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_WRITE_MEM);
-       Endpoint_Write_Byte(ReturnStatus);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_WRITE_MEM);
+       Endpoint_Write_8(ReturnStatus);
        Endpoint_ClearIN();
 }
 
                  ReturnStatus = XPRG_ERR_TIMEOUT;
        }
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_READ_MEM);
-       Endpoint_Write_Byte(ReturnStatus);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_READ_MEM);
+       Endpoint_Write_8(ReturnStatus);
 
        if (ReturnStatus == XPRG_ERR_OK)
          Endpoint_Write_Stream_LE(ReadBuffer, ReadMemory_XPROG_Params.Length, NULL);
                ReturnStatus = XPRG_ERR_FAILED;
        }
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_CRC);
-       Endpoint_Write_Byte(ReturnStatus);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_CRC);
+       Endpoint_Write_8(ReturnStatus);
 
        if (ReturnStatus == XPRG_ERR_OK)
        {
-               Endpoint_Write_Byte(MemoryCRC >> 16);
-               Endpoint_Write_Word_LE(MemoryCRC & 0xFFFF);
+               Endpoint_Write_8(MemoryCRC >> 16);
+               Endpoint_Write_16_LE(MemoryCRC & 0xFFFF);
        }
 
        Endpoint_ClearIN();
 {
        uint8_t ReturnStatus = XPRG_ERR_OK;
 
-       uint8_t XPROGParam = Endpoint_Read_Byte();
+       uint8_t XPROGParam = Endpoint_Read_8();
 
        /* Determine which parameter is being set, store the new parameter value */
        switch (XPROGParam)
        {
                case XPRG_PARAM_NVMBASE:
-                       XPROG_Param_NVMBase = Endpoint_Read_DWord_BE();
+                       XPROG_Param_NVMBase = Endpoint_Read_32_BE();
                        break;
                case XPRG_PARAM_EEPPAGESIZE:
-                       XPROG_Param_EEPageSize = Endpoint_Read_Word_BE();
+                       XPROG_Param_EEPageSize = Endpoint_Read_16_BE();
                        break;
                case XPRG_PARAM_NVMCMD_REG:
-                       XPROG_Param_NVMCMDRegAddr = Endpoint_Read_Byte();
+                       XPROG_Param_NVMCMDRegAddr = Endpoint_Read_8();
                        break;
                case XPRG_PARAM_NVMCSR_REG:
-                       XPROG_Param_NVMCSRRegAddr = Endpoint_Read_Byte();
+                       XPROG_Param_NVMCSRRegAddr = Endpoint_Read_8();
                        break;
                default:
                        ReturnStatus = XPRG_ERR_FAILED;
        Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPNUM);
        Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
 
-       Endpoint_Write_Byte(CMD_XPROG);
-       Endpoint_Write_Byte(XPRG_CMD_SET_PARAM);
-       Endpoint_Write_Byte(ReturnStatus);
+       Endpoint_Write_8(CMD_XPROG);
+       Endpoint_Write_8(XPRG_CMD_SET_PARAM);
+       Endpoint_Write_8(ReturnStatus);
        Endpoint_ClearIN();
 }