usb stick not recognized in single user mode

Hi!
The title pretty much says it all: When booted in single user mode, I can't get my machine to recognize the USB drive. Here's what I did:
1. inserted usb stick (memorex 4GB traveldrive, msdos filesystem)
2. booted in single user mode (cmd+s after powering on)
3. mount -uw /
3. looked for usb device in /dev
4. ...it's not there! The USB drive shows up as /dev/disk1s1 after an ordinary boot, but in single user mode it's nowhere to be found. It's not just a name issue either: the list of devices that appear in /dev in single user mode is the same whether or not the USB stick is plugged in.

Even more confusingly, out of the 10(?) times I tried this it worked twice: /dev/disk1s1 actually appeared.
mkdir /mydirectory; mount -w -t msdos /dev/disk1s1 /mydirectory
worked fine, and I was able to read/write from the stick as usual. I have no idea what I did differently those two times.

Does anybody know what's going on? I've got a MacBook2,1 running vanilla Leopard.

Thanks for taking the time to read this, and thanks in advance for your help

Problem (though I still don't know what it was) solved. Latest firmware update makes the USB device appear consistently.

sorry for the double post, just making sure nobody wastes their time.