Raspberry Pi Installation Help?

[syaochan]

I tried to add uas in /etc/modules and then in cmdline.txt with load-modules=uas, but cannot get it to load at boot, but this seems a minor issue at the moment.
The main problem is that the first boot from USB (manually loading uas and mounting rootfs) is ok, after that it does not boot anymore, not even in recovery console. All I get is a blinking cursor at top left of the screen, no prompt, I can type anything I want but nothing happens.
This happens both flashing the USB disk using xbian copy tool from a working copy of xbian on SD card, or flashing directly the image to USB disk.
I tried to add debug option to cmdline.txt, but nothing change. Not even rescue_early helps.