Booting Linux from USB-ZIP on older systems

Booting Linux from USB-ZIP: If you have an older computer system, your BIOS might not support USB-HDD boot. In this case, it may still be possible to boot Linux from USB if your BIOS does list USB-ZIP as a boot option. We can trick the BIOS into thinking that the USB flash drive is a zip drive.

This process involves manipulating the geometry of the USB drive to resemble that of a zip disk drive, which the BIOS recognizes as bootable. Let’s walk through the steps on how to make it happen.

Booting Linux from USB-ZIP Prerequisites

We can trick the BIOS by modifying the number of heads and sectors being displayed from the USB flash device to match that of a zip drive. Then we partition the drive using partition 4 (the partition that zip drives typically use). For this tutorial we will use the mkdiskimage application that comes with syslinux.
Warning: This tutorial is old and may be outdated. I have not tried this on USB flash drives larger than 1GB. Backup any information you wish to save before proceeding.

Ubuntu or similar running Linux environment.
USB flash drive (tested to 1GB) with a Live Linux Distro Installed.
Old system BIOS with USB-ZIP listed as a boot option.

Tricking the BIOS into Booting Linux from USB-ZIP

In this section, we will guide you step by step on how to modify the geometry of your USB flash drive and make it bootable.

Before proceeding, see how this process works to trick the BIOS in the USB Keys Syslinux document under the "mkdiskimage section". I am using a running Ubuntu operating environment to perform these BIOS tricking steps:

Insert your USB flash drive
Open a terminal Ctrl+Alt+T
Type or copy and paste each of the following commands into the open terminal window, pressing Enter after each command.
If you don't have syslinux installed, install it using:
```
 sudo apt-get install syslinux
```
And if you don't have mtools installed, you'll need it as well:
```
sudo apt-get install mtools
```
Next, to list the available disks, use the following command:
(making note of your flash drive from the resulting list)
```
sudo fdisk -l
```
Then, enter the following command:
(replacing x with your actual flash drive letter)
```
sudo mkdiskimage -4 /dev/sdx 0 64 32
```
After the process has completed (takes a while) to confirm the new geometry of the flash drive:
```
sudo fdisk -l
```
(it should now read "64 heads, 32 sectors")
Finally, to make the drive Linux bootable, enter the following command:
(replacing x with your flash drive letter)
```
sudo syslinux /dev/sdx4
```

Troubleshooting Tips

USB-ZIP Not Available in BIOS Boot Menu: If your BIOS doesn’t show USB-ZIP as a boot option, it’s possible that your BIOS is outdated or doesn’t support this feature. Check for any available BIOS updates from your motherboard’s manufacturer.
Drive Not Booting: If after all steps, the USB drive doesn’t boot, ensure that the BIOS is set to boot from USB devices. You may need to check the boot order in your BIOS settings.
Repartitioning Issues: If you face issues with partitioning or formatting, ensure you’re using the correct partition number (i.e., partition 4) for the Zip geometry trick. You can also try using fdisk to check for partition consistency.

Frequently Asked Questions

Can I use a USB drive larger than 1GB for this process?: While this tutorial was tested on a 1GB USB drive, larger drives might not work reliably due to the geometry trick. It’s recommended to use smaller USB drives, ideally 1GB or less, for the best results.
What is the USB-ZIP option in BIOS?: The USB-ZIP option in BIOS makes the computer treat a USB drive as if it were a Zip disk, which some older systems can boot from. This is useful when your system doesn't support booting from USB-HDD or USB-FDD.
What if USB-ZIP is not listed in my BIOS?: If USB-ZIP is not listed as a boot option in your BIOS, unfortunately, this method will not work for your system. You might need to check if there is a BIOS update available, or consider other boot options such as using a different bootloader or bootable CD/DVD method.
Can I reverse the changes made to the USB drive?: Yes, you can reverse the changes by reformatting the USB drive. The process described here alters the drive’s partition structure, so reformatting it back to its original file system (e.g., FAT32) will restore the drive to its previous state.
Why do I need to modify the disk geometry?: The modification of the disk geometry tricks the BIOS into thinking that your USB flash drive is a Zip drive (USB Zip Drive), which is recognized as bootable by older BIOS versions. This trickery makes the drive bootable on older systems that might not recognize a USB-HDD as a valid bootable device.
What should I do if my USB drive still isn’t booting?: If your USB drive is not booting after completing the steps, ensure that the BIOS is properly set to boot from USB devices. Double-check that USB-ZIP is the first boot device. If issues persist, the USB drive might not be compatible with this method, and you might want to try using another USB drive or investigate alternative methods such as using a bootable CD/DVD.

Final Thoughts

By following these steps, you can trick an older BIOS into booting Linux from a USB drive, even if it doesn’t support USB-HDD boot. This method is especially useful for older systems that may have limited boot options but still support USB ZIP Boot. If you run into problems, feel free to consult the Syslinux USB Key documentation for further details and troubleshooting. Happy booting!