Creating a bootable USB drive is a simple task that will serve us for different functions. The basic idea is to create a bootable media for use before loading the installed operating system on the internal drives of a PC. We could also use optical media like a DVD, but using USB is much safer, more versatile, and easier to implement and maintain.
What are they used for and why are they so useful?
A typical use of these media is installation of operating systems, whether new, for reinstalls, or to use as rescue environments. Another group of interesting functions are what we call “USB-Live”, complete operating systems that can be run from the same medium. Most are GNU/Linux distributions, but there are also others with Windows. They serve for testing or as troubleshooters and/or maintenance.
Another important focus for these bootable media is cybersecurity. Not all types of malware can be combated once the main operating system has started because they load themselves into memory making them difficult to detect and remove. The use of an external medium independent of the PC to be analyzed is a ideal (and sometimes only) solution to keep your computer safe from viruses and Trojans.
And the same can be said for a certain group of software that need to act before the loading of the main operating system. Take for example the MemTest memory module testing tool which needs to be used on a bootable drive as the memory test needs to be done before the operating system is loaded.
How to create a bootable USB drive
For this tutorial and as an example we are going to create a Windows 11 installation medium. For the rest of the uses mentioned, its creation is very similar and basically consists of downloading an image (usually ISO) and what is known as “burning” (burn) to the USB by making it bootable media.
Step 1. Select the USB
USB is a tremendously compatible interface that is present on any computer. The media is very cheap and you can use external flash drives, hard drives or SSDs of any version of the interface, from USB 2.0 onwards. Higher versions will increase performance (important for USB-Live), while lower versions usually offer better compatibility.
As for size, you can use whatever you want as long as you have room for the function in question. To install Windows or Linux operating systems, 8 GB is enough. In our case we will use a USB 3.1 flash drive with a capacity of 64 Gbytes.
Step 2. Download the image
In the case of Windows 11, which we give as an example, it is as simple as downloading it from its official page. Microsoft -finally- has made things easier and the system image can be downloaded directly without going through a wizard that takes considerably longer and is not as effective as the tool that we will use for the recording. If you are going to use it for Linux or other uses like rescue antivirus the same, you will have to download the image.
Access the Microsoft portal for Windows 11 and click on “Download Windows 11 disk image”. Select Windows 11 (multi-edition ISO) and the language, to get a download link “Windows 11 Spanish” 64 bits. Save it in any location.
Step 3. Create the installation media
There are a dozen applications to carry out the process of “burning” the image. For the example we use our favorite app, Rufus, which is free and works great especially with Windows images. Download and run.
We insert the aforementioned USB pendrive into an empty port and run Rufus. You will see a very simple interface where you will first have to select the downloaded Windows image by selecting the “Boot Choice”. It only remains to configure the rest of the options. GPT in “partition scheme”, target system “UEFI (not CSM) and NTFS as file system. There are other configurations, but that is the typical one if you are going to install the system on new machines. It only remains to wait a few minutes for the application to complete the process.
Step 4. Manage BIOS/UEFI
With the previous step we will have already created our installation medium, but to use it, we must access the BIOS/UEFI of the computer. As we explained above, it is a medium that we intend to boot before the internal storage units are started and the boot order is a management that is carried out there.
With the USB inserted, we restart the equipment and access the firmware. Each BIOS is different, but the goal with all of them is to place the installation media as the first boot device. We do; We save and restart the computer. If the USB medium is well created, we will boot on it without major problems.
As we said, it is a simple example of creating a bootable USB drive with Windows 11, but in the same way we can create a self-bootable medium to run a GNU/Linux distribution, as a means of maintenance, rescue or repair, for disinfection of viruses or other tools that need to be run from these media. Very useful.