Dual Boot RebornOS & Windows UEFI (Expanded) – by linuxhelmet

(By Bonnom from Antergos)

Hardware & Software Requirements

(1). Pre-existing Windows 10 device or other operating system (x64).
(2). External HDD / USB flash drive / cloud storage to backup personal files.
(3). USB flash drive for Windows live recovery media (16gb or larger recommended).
(4). Decent internet speed to download and install RebornOS ISO.
(5).Software to burn RebornOS live install ISO onto USB flash drive.
(6). USB flash drive for RebornOS live install media (4gb recommended).


(1). Back up all pictures, documents and other personal files onto an external storage location. This can be a external HDD, a USB flash drive, or even onto your choice of cloud storage. Just ensure that all your files are backed up so as to prevent data loss during the RebornOS installation process.
(2). Write down or acquire any product keys for paid software to prevent loss of software if something does fail during the installation process.
(3). Be prepared with two USB flash drives. One drive will be used to create the live recovery media for Windows, while the second drive will be used to make the live media for RebornOS.
(4). Decent or fairly fast internet is needed to download the full live install ISO for RebornOS. The ISO itself is 2.1 GB roughly and depending on internet speeds the install will require a solid internet connection during the install process. Install can take 30 min. and up depending on internet speed.

Backup Windows Operating System

This is a practice that is recommended regardless of if you are installing a new operating system or just trying to recover your existing Windows.

(1). You can find the Recovery drive creator by opening Control Panel (Windows key + S)
(2). Type in Control Panel
(3). In the Control Panel you can either search for Recovery in the Search Content box OR change View by: Category to View by: Large Icons
(4). Open Recovery
(5). Click Create a recovery drive
(6). Insert the USB flash drive (16 GB or <)
(7). WARNING: Make sure nothing important is on the flash drive before starting this process!
(8). It's recommended to check the box stating Back up system files to the recovery drive before clicking next.
(9). Make sure you know which drive is your flash drive before continuing.
(10). Proceed to follow prompts to create recovery media. This may take some time. When done proceed to safely remove the USB flash drive.

Downloading the RebornOS ISO

If you are starting with Windows as your main operating system software is needed to create the RebornOS Live USB. Popular software for this include programs such as Rufus or Etcher. To do so, simply download either of the tools and then, for Rufus simply follow the instructions here. For Etcher, simply select the desired ISO and the drive, and then hit Flash!



Another option if you are using a Linux operating system is to use the following commands in terminal to create the live USB of RebornOS:

sudo su
cd Downloads
cat RebornOS.iso > /dev/sdX

Downloads is where I saved my RebornOS ISO sdX is just a placeholder. Replace the X with your proper location for your flashdrive (in my case this was /dev/sdb) rebornos.iso is also a placeholder. You can right click on the iso and go to “Rename” where you can just copy the name into terminal.

To find out where your flashdrive is located use the following command:

This will spit out all of your sda/sdb/sdc ect. outputs. Find your usb then replace that with sdX (As far as I know you won’t need the drive numbers only the drive letters Ex: sdb NOT sdb1)

Install RebornOS

The GNOME-based RebornOS installer will automatically start with the following screen:


Clicking on "Install it" will bring up the language selection screen for the installation:


The following screen will check the requirements for the installation:


The next screen will allow you to select your location:


The next screen will allow you to select your timezone:


The next screen will allow you to select your keyboard layout:


The next screen will allow you to choose your desktop:


The following screen allows you to select different installation options:


The following screen allows you to select (optional) the cache partition:


The following screen allows you to select the mirror options:



When you come at the screen, select the second option (Choose EXACTLY where RebornOS is Installed). If you choose the first option, you’ll lose Windows. In the second option, we’ll manually edit the partition and tell the system where to install RebornOS:


Side note:
Using a mb to gb converter is an great way to calculate how much you want to shrink and define all your partitions.

You’ll see a partition table, something like the one below. If you have already made some free space, you should be able to see it. If you have not, just delete some partition (except C drive):


Select the free space partition and click on + New. Now, create a Root partition. Root partition is where the operating system and the applications will be installed . An amount of 15-20 GB should be sufficient for it. But if you could give it more, it would be better.

The root partition will be type ext4 and type Primary.


Next is to create the /boot/efi partition. Actually, we don’t need to create it! Windows already has it. We can just specify the path to it. Just make sure to NOT format it.



NOTE: Even if you are re-installing RebornOS on a dual boot DO NOT format the /boot/efi partition. Only edit it.

In the screenshot of partition table, see the /dev/sda2 partition. This is where UEFI settings are and this where the system decides how to boot. The sda number could be different for you, but the label should be ESP and the type fat32. Select it and just add the mount point as /boot/efi

So, we have root, we have boot. Now make Swap partition around the size of your system’s RAM. If you have more than 4 GB of RAM, swap memory size should be half of the size of RAM.



Swap is an important part of any system. Without swap memory certain programs can crash or cause errors without it. Swap is a good practice but NOT required. You may go without this step AT YOUR OWN RISK. I always dedicate at least 2-4gb of swap to keep things from going haywire. But to each his/her own.

And in the similar fashion, create a Home directory. Home directory is where your documents, downloaded files and music will go.


That’s it. We have root, boot, swap and home. We are good to go. Hit on Install now to proceed with the installation:


Rest of the things are again a walk in the park. You’ll be asked to enter a username and password. I presume that you know what to do here:



There were a few elements I found that the author did forget to mention is after you install RebornOS. I will add these steps as well as how to re-install RebornOS should something go wrong.

Finding Windows 10 for Grub

Once you are inside your nice new RebornOS, you may notice that on boot up you are given an option for RebornOS or Troubleshooting in grub but NO option for Windows. Don’t freak out your Windows should NOT be gone.

Go into RebornOS, find terminal and type in the following command:
sudo os-prober

Once this is done it should list something similar to what I have below:
/dev/sda2@/EFI/Microsoft/Boot/bootmgfw.efi:Windows Boot Manager:Windows:efi

If it didn't find the windows partition you might have to install the ntfs-3g package using the following:
sudo pacman -S ntfs-3g

Great! You found it. Now to update your grub so that it can see it.

Update grub:
grub-mkconfig -o /boot/grub/grub.cfg


Final OPTIONAL Tweaks

Now you should see both RebornOS and Windows 10 on /dev/sda2 when you start your machine. You can now use the arrows to select either option. But wait…what if you need longer to decide or you don’t want to have to wait 5 seconds for it to automatically select Reborn OS?

Go to terminal and edit grub for faster/slower countdown:
sudo nano /etc/default/grub

Your grub file should show up. In nano you can use CTRL + O to save and CTRL + X to exit. Be CAREFUL with this file. To edit your countdown time look for the following lines:

You can now change the GRUB_TIMEOUT to the number in seconds you desire. (Don’t use 0 seconds unless you don’t want to be able to select an option!) I personally like a 1 second countdown due to rarely using Windows. My grub looks like the following:

CTRL + O to Save the document then CTRL + X to exit back into terminal. Next you want to update your grub file by using the following:
grub-mkconfig -o /boot/grub/grub.cfg