How to install Ubuntu Feisty Alternate installer on a USB Flash Drive

After much searching, I found the instructions at https://help.ubuntu.com/7.04/installation-guide/i386/boot-usb-files.html

These didn't work for me:
http://learn.clemsonlinux.org/wiki/Ubuntu:Install_from_USB_drive
https://help.ubuntu.com/community/Installation/FromUSBStick

Note: with the syslinux that comes with Ubuntu 7.04, you have to format the partition as FAT16 (type 6) and specify the FAT type when using mkdosfs:

$ mkdosfs -F 16 -n UBUINSTALL /dev/sdX1

Download boot.img.gz, initrd.gz, vmlinuz from http://archive.ubuntu.com/ubuntu/dists/feisty/main/installer-i386/current/images/hd-media/

and copy to root of target

Unmount the target device

$ syslinux /dev/sdX1

Create file syslinux.cfg in root of target

  default vmlinuz
  append initrd=initrd.gz ramdisk_size=12000 root=/dev/ram rw

Copy iso image into root

$ cp ubuntu-7.04-alternate-i386.iso /media/disk/

Install the Master Boot Record (after unmounting the target device):

$ sudo apt-get install mbr
$ install-mbr /dev/sdX

Should be ready to boot