I’ve had an ongoing issue since putting Debian on the NSLU2 that the device would not let me connect after a restart. It turns out that it hadn’t restarted properly. The resolution I found was to ensure the disk is plugged into the DISK 1 port.
If you are using a Y-cable like I am then primary USB plug should be plugged into DISK 1.
Looks like I can setup the scheduled restart again now.