Hi Einar,
I'm using 2 usb sticks for testing: Corsair (32BG) and Doulos (128MB) both formatted with vfat. My board contains NXP ISP1520 USB Hub. Neither of these sticks are being detected correctly, in fact the Corsair is not detected at all.
I have tested successfully the Doulos stick on another board with mpc5200 which don't have any USB Hub, just using the 2 on-chip ports. The Corsair stick is not working, halts the cpu.
If you have spare hardware, are you able to remove and bypass the hub to determine if you still see the same u-boot issues? Conversely, are you able to connect this hub (for example a dev kit or a commerical hub with this chipset) to the MPC5200 to see if you still have issues? I'm trying to determine the hub's role, if at all possible.
Other than that, I'm a little short of ideas. Potentially some timing since (IIRC) the mpc5200 is full-speed not high speed? I'm kind of clutching at straws here.
Maybe someone with a bit more knowledge about USB can make a more informed comment.
-- Damien