Installing Debian from a USB stick
Credit to dilinger for this one.
Partition the USB stick (some come unpartitioned and expect you to mount the full device; that won’t work here). Make the partition bootable, type Linux (0×83).
We’ll assume the device node for the partition is /dev/sda1 from here on.
mkfs.ext3 -m 0 /dev/sda1 mount /dev/sda1 /mnt grub-install –root-directory=/mnt /dev/sda mkdir -p /mnt/boot/grub
Save menu.lst into /mnt/boot/grub/
Save the appropriate vmlinuz and initrd.gz files and an install ISO into /mnt/
If you don’t have these already, try here and here (use the “netinst” or “businesscard” ISO images unless you have a good reason to need the whole image and a > 512MiB flash drive).