I have modified C:\Freescale\Freescale_MQX_4_0\usb\device\examples\msd example to USB SDcard MSD and its working fine on twrk60n512 . Now I want to increase the speed of data transfer over USB. I defined HIGH_SPEED_DEVICE to 1 to improve the speed, but now the program is going to despatch.s. Will this work correctly or i went wrong somewhere? Can anyone help on this to improve data transfer rate over USB.