How to make a USB flash drive bootable like a CD made from an ISO

All we need is an easy explanation of the problem, so here it is.

Apparently my installation of syslinux was incorrect and liveusb-creator installs it somewhat correctly. Now I am getting the error “chain.c32: not a COM32R image”. How do I make a USB flash drive bootstrap like a CD? My BIOS is configured okay (Ubuntu boots from USB).

The problem is, I have an ISO image and if a burn it to CD it boots fine. When I “burn” it to the flash drive, it doesn’t boot.

I am guessing the CD burner creates a sort of a boot sector automatically, which isn’t done for the USB drive. Please do not refer me to Linux/Ubuntu bootable installers from USB, I am not asking to boot Linux. It’s an arbitrary bootable ISO image.

The ISO contains an isolinux directory, inside is some stuff like file, isolinux.bin, .img file, .krn file etc. Ring any bells? I am not familiar with this isolinux bootloading thing.

Can someone please explain how I can use these files? Do I need to reinstall syslinux on the USB?

Apparently my installation of syslinux was incorrect and liveusb-creator installs it somewhat correctly. Now I am getting the error:

“chain.c32: not a COM32R image”

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

I’ve had succes with both Windows and Linux iso’s using UNetBootin.
There are also several tutorials out there on how to use it with a Windows ISO.

Method 2

HP has a couple tools that can be used to make USBs bootable. I’ve had mixed success with them depending on what it is I’m putting on them. Their strength, apparently, is that they are supposed to work with anything.

The HP Drive Key Boot Utility is one:

The HP USB Disk Storage Format Tool is another. It works best for creating MS-DOS style boot disks:

Method 3

I use liveusb-creator. It was designed for Fedora, but it’s worked with every other live ISO I’ve put on it.

Method 4

There are several known issues with a unetbootin and several flavours of Linux. It can work but if like me you find it causing issues, I have had more luck with Rufus.

Method 5

This answer was provided by the OP as an edit to the question.

Unetbootin worked for me in the end. Installed syslinux correctly, though I had to use an older version 494. The new version produced an error:

“menu.c32: not a COM32R image”.

The problem was with syslinux installation on USB (syslinux is a lightweight bootloader). I’ve tried installing it from Linux terminal, didn’t work.

Method 6

A USB drive can be substituted for a CD most of the time when making accurate, error-free bootable media, and it also eliminates the risk of creating a badly burnt CD. There are many programs available for making Linux live USBs. Universal USB Installer is one of the best ones. Click the Supported Distros tab on the linked webpage to show the list of supported Linux distributions. Universal USB Installer is updated regularly, as the supported Linux distributions are updated, so it is best to download the latest version.

Rufus is another program for making Linux live USBs.

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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