If you want repeat a test, some detailed explanation is here:

A. You need a modified kernel build from 2.6.28-20100903+0m5. A default kernel configuration arch/arm/configs/rx51_defconfig should be modified:

1 - remove CONFIG_USB_OTG_WHITELIST and CONFIG_USB_OTG_BLACKLIST_HUB options.

2 - Apply an attached patch (u.txt) to kernel sources.

3 - Build a kernel.

B. Boot a kernel

C. Connect to PC and answer "PC Suite" to mode question.

D. echo host >/sys/devices/platform/musb_hdrc/mode
You should see in /var/log/syslog a message "twl4030_set_host() after 4030 OTG_CTRL=0x26" - the '2' is a significant.

E. echo H >/proc/driver/musb_hdrc

F. reattach USB cable from PC to self powered USB hub with memory stick or to external hard disk.

E. Look into /var/log/syslog - You can see a lot of messages and two are most valuable - "Initializing USB Mass Storage driver" and "
USB Mass Storage support registered". And in between you may see "scsi0 : SCSI emulation for USB Mass Storage devices".

F. After some time the scanning finishes and you may execute

mount /dev/sda1 /mnt

(check /dev/sda1 first!)

Viola!

If somebody could repeat it - it would be a very good information, I worries about some HW differences or wrong setup of D+/D-.

I also attach a copy of my log for reference (a lot of debug output here).

Note: ke_recv has some problem with storage recognition and it is a reason why a manual mount is needed. Don't forget to unmount before cable detachment. Or just switch N900 OFF.