@cehofer
does your A1XE have the 'DMA fix' by any chance? in any case USB on those boards is a tad wonky if you're using the on-board USB support. and, like the pegasos2, it's limited to USB1.1 speeds. a few questions for you:
1. you say you updated from update 1 to update 6 -- did you update sequentially, i.e., install update 1, then update 2, then update 3, and so forth?
2. are you using on-board USB or USB via a PCI card?
3. if using the on-board USB, have you tried commenting out "MODULE Kickstart/ehci.usbhcd" in SYS:Kickstart?
USB support in current versions of AOS4 is pretty good, and much, much faster than before. let's try and figure out why you're having trouble.
-- eliyahu