1The proper mode to boot a USB key drive in is "USB-HDD". That is the 2ONLY mode in which the C/H/S geometry encoded on the disk itself 3doesn't have to match what the BIOS thinks it is. Since geometry on 4USB drives is completely arbitrary, and can vary from BIOS to BIOS, 5this is the only mode which will work in general. 6 7Some BIOSes have been reported (in particular, certain versions of the 8Award BIOS) that cannot boot USB keys in "USB-HDD" mode. This is a 9very serious BIOS bug, but it is unfortunately rather typical of the 10kind of quality we're seeing out of major BIOS vendors these days. On 11these BIOSes, you're generally stuck booting them in USB-ZIP mode. 12 13THIS MEANS THE FILESYSTEM IMAGE ON THE DISK HAS TO HAVE A CORRECT 14ZIPDRIVE-COMPATIBLE GEOMETRY. 15 16A standard zipdrive (both the 100 MB and the 250 MB varieties) have a 17"geometry" of 64 heads, 32 sectors, and are partitioned devices with a 18single partition 4 (unlike most other media of this type which uses 19partition 1.) The 100 MB variety has 96 cylinders, and the 250 MB 20variety has 239 cylinders; but any number of cylinders will do as 21appropriate for the size device you have. For example, if your device 22reports when inserted into a Linux system: 23 24usb-storage: device found at 4 25 Vendor: 32MB Model: HardDrive Rev: 1.88 26 Type: Direct-Access ANSI SCSI revision: 02 27SCSI device sda: 64000 512-byte hdwr sectors (33 MB) 28 29... you would have 64000/(64*32) = 31.25 cylinders; round down to 31. 30 31The script "mkdiskimage" which is supplied with the syslinux 32distribution can be used to initialize USB keys in a Zip-like fashion. 33To do that, calculate the correct number of cylinders (31 in the 34example above), and, if your USB key is /dev/sda (CHECK THE KERNEL 35MESSAGES CAREFULLY - IF YOU ENTER THE WRONG DISK DRIVE IT CANNOT BE 36RECOVERED), run: 37 38 mkdiskimage -4 /dev/sda 0 64 32 39 40(The 0 means automatically determine the size of the device, and -4 41means mimic a zipdisk by using partition 4.) 42 43Then you should be able to run 44 45 syslinux /dev/sda4 46 47... and mount /dev/sda4 and put your files on it as needed. 48