I'm developing on MQX an USB Host that read and save a configuration from an USB mass storage (USB device), an external MRAM is mandatory? I saw that MFS and USB Host use a lot of RAM ... an application of example inside MQX like \Freescale MQX 3.5\mfs\examples\mfs_usb can work correctly without external RAM?
Of course you can implement a demo with only internal RAM, MCF52259 has 64KB on-chip RAM which should be enough for this purpose, MRAM is not mandatory.