The USB hub has to be powered, because I don't think that the device is able to power 2 usb sticks.
After you took care of this, you need to make sure, the USBs are mounted correctly. During bootup the order of the USB sticks can be changed, ie first boot,the stick containing the PirateBox-executables is (like expected) /dev/sda ... next boot is /dev/sdb , which causes the box not to work.
To ensure this, you have to change /etc/config/fstab that it uses the uuid to mount [wiki.openwrt.org]
hope that helps
Matthias
After you took care of this, you need to make sure, the USBs are mounted correctly. During bootup the order of the USB sticks can be changed, ie first boot,the stick containing the PirateBox-executables is (like expected) /dev/sda ... next boot is /dev/sdb , which causes the box not to work.
To ensure this, you have to change /etc/config/fstab that it uses the uuid to mount [wiki.openwrt.org]
hope that helps
Matthias