i am trying to implement USB MSD device bootloader using Kinetis K20, CodeWarrior 10.4, processor expert and MQX lite OS. I think there is a problem with USB somewhere because my device is correctly enumerated and i can see file in BOOTOLOADER MSD drive when i attach my device to computer. Problem is when i try to write file to MSD drive. Windows reports timeout writing after few minutes. I did some debugging in MSD_Event_Callback function found in disk.c and figured out that USB_MSC_DEVICE_WRITE_REQUEST case is NEVER reached. Any advice would be appreciated.