As USB flash drives are currently one of the most popular digital supports to store information and have replaced the outdated CDs, you will find below some methods to make a bootable ISO image (which can upload and install an operating system) from such an external memory. The options presented below are some of the most frequently used with the best results. It’s not a simple copy paste operation, it involves creating the necessary files that allow the USB memory drive to boot when connected to a device.
1. How to make a bootable USB stick for Linux
You can make a bootable USB drive using program called Universal USB installer which has become very popular in recent years. This program works very well on Windows operating systems and can create a bootable flash drive from a wide variety of distributions.
The interface is quite simple. You only have to download the installation kit of the OS which you need in ISO format, check from the application list the name of the respective distribution device and by clicking browse, choose the previously downloaded file. After going through these stages and chosen the respective letter of the USB memory drive click on “Create” and you start setting up your bootable stick.
2. Linux Bootable USB from an IMG image
Some Linux distributions are available for download only in IMG format, instead of ISO. This type of RAW files must be written directly on a USB storage medium.
For this you can use Win32 Disk Imager. You can download it here and this utility also works for burning an IMG content on a USB drive.
Linux users can use a very simple command line for this task. With a USB drive or SD card connected to the PC, open a terminal window and enter this command, without quotes :
,,sudo dd if=/home/user/file.img of=/dev/sdX bs=1M”
You only need to replace the command /home/user/file.img with the exact location of the IMG source file. Also, /dev/sdX is the path to the memory stick which you need to customize according to your operating system.
If you make a mistake and it stays in your boot partition you risk corrupting it with the content of the CD image, in which case your computer will no longer turn on.
3. How to make a bootable USB stick Windows 7 from an ISO file ?
Use the the tool created by Microsoft: Windows 7 Usb/Dvd Tool. This tool can be downloaded from the official website and works for both creating USB drives and bootable SD cards, as well as DVD's.
You need the Windows IMG file and then just follow the steps given by the program. During the first stage choose the ISO format source, in the second stage select the destination storage medium, USB device or DVD and in the third stage wait a few minutes until the process ends.
4. How to make a bootable USB flash drive with Windows 8 or Windows 8.1 having a licence key?
If you have an installation key for Windows 8 or Windows 8.1, you can download the installer directly from the Microsoft website. In this way you can get an ISO which you can use afterwards or you can create a bootable USB stick right away. There is a web page which has been created for the whole process and it was suggestively called Upgrade Windows with only a product key. There you can download a utility of a few MB, enter your licence code and follow the two or three steps by checking/ticking the creation of a “USB flash drive”.
If you don’t have a code for the most recent Windows version, it is best you install Windows 8 and afterwards make a free upgrade to the Windows 8.1 version.
How to make a bootable Windows 8 and Windows 8.1 USB flash drive from an ISO file
If you already have a Windows 8 or Windows 8.1 ISO file which you want to use for the installation of the OS from a USB stick, to create the booting medium, by using the same utility Windows 7 USB/DVD download tool. Instead of the Windows 7 file, you will choose the Windows 8 or 8.1 one but otherwise the steps to be followed are the same.
How to create a bootable USB to install OS X
The most recent OS X, Mavericks, can be downloaded for free from the Mac AppStore. In order to transfer the respective file on a USB drive you have two options.
You can use a line of command in the terminal, such as ,,createinstallmedia” or more intuitively, you can use the utility DiskMaker X, downloadable for free from the Mac AppStore or from here.
There is another way but it’s not as easy. Download OS X Mavericks, and afterwards the Install OS X Mavericks message should appear in Applications. Next launch the line of command below which I recommend you copy. (no quotes –of course)
,,sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia –volume /Volumes/Name –applicationpath /Applications/Install\ OS\ X\ Mavericks.app –nointeraction”
The only change you need to do in your system is to replace the word Name, in bold, with the name of your USB flash drive as it appears in Finder (sometimes the name is Untitled). The bootable stick thus created can be used to install the most recent version of OS X on any Mac or to update a system which has an older version of the operating system made by Apple. Although the OS itself is free with such a memory stick you can rid yourself of long downloads.
Bootable USB drive from an ISO with Windows on Mac
The safest and most frequently used method to run Windows on Mac systems implies the BootCamp system which you can find in Utilities.
The main advantage is that Boot Camp will transfer the content of an ISO with Windows 7, Windows 8 or Windows 8.1 on a USB memory and will include on the same storage medium and all the drivers necessary to run the new operating system.
To get back into OS X you need the Boot Camp utility installed on the Windows USB drive achieved through the Assistant. Boot Camp can be used to install Windows on any Mac, but not to install Windows on a PC.
These are the main methods but of course you can try other utilities that haven’t been mentioned here if none of the above solutions will satisfy all your requirements. Good luck!