I am considering of doing the same migration on M52277EVB. Have you made any progresses?
I have already developed a bootloader based on MQX, MFS and USB stack, but its size is way too big. I tried MQX 3.5 which allows me to have a smaller RTOS configuration. But the bootloader size is not shrinked too much. That is why I am thinking of taking this example.
Asking my local Freescale FAE about the migration, I was told the MCF5227x uses a different USB periperals and Freescale is working on a MQX USB bootloader but still much larger than this example.