Dual boot Batocera

It is recommended to boot Batocera off of a USB/other external drive and to use your BIOS boot selection menu to switch between Batocera and other operating systems that may already be on other drives. You can still use drives with other operating systems on them to host your userdata such as ROMs, BIOS files, saves, etc. This is the far simpler option to do instead of what you'll have to do if you only want to do everything from one drive. However, some people prefer to have Batocera directly installed on the main hard drive alongside another pre-existing OSes, this page is for that.

Before attempting any of this, make a backup of your data. There is a chance that the following actions (shrinking partitions, replacing boot loaders, etc.) can render the storage devices inoperable.

If this sounds too spooky to you, just flash Batocera to a USB drive as is recommended and use that instead.

Ordinarily, Batocera utilizes Syslinux to boot, which is configured to only boot Batocera. Thus, for most dual boot setups we will be utilizing GRUB to show a boot selection menu after BIOS has loaded instead.

In case you install Batocera on your hard-drive, you may want to rename the BATOCERA partition to something unique like BATOPC. If you do, edit the grub.cfg file below to have label=BATOPC instead of label=BATOCERA. This allows you to still boot using Batocera installed on a USB without worry that the hard-drive will always take priority due to sharing the same label.

For those that prefer video guides (there is… no actual need to flash a spare USB drive, just download the boot.tar.xz): Pleilleur's Choice #1 Dualboot Windows 10 and Batocera

This guide is assuming Windows is being booted from an EFI partition. If it isn't, or you don't know, proceed at your own risk.

Preparing the drive

Partition the drive, having a 8 GB FAT32 partition after the Windows drive immediately followed by the “userdata” partition, which can be any compatible filesystem. If preferred, it is also possible to have Batocera to use the Windows partition as its userdata, however that requires manually setting it up before the rest of the installation so for first-timers this is not recommended.

Extract and copy the latest Batocera ''boot.tar.xz'' (can be extracted with 7-zip) to the root of the FAT32 partition. Its contents should look similar to the following:

D:\
├─ boot\
├─ EFI\
├─ tools\
└─ batocera-boot.conf

Installing GRUB over Windows' boot manager

Download and install grub2win. It may come up as a false positive on anti-virus software, we are going to be overiding the boot manager which could potentially prevent Windows from booting so maybe they are right in that regard. Either way, just let it through to continue.

  1. Extract the grub2win ZIP, and run setup.exe.
  2. Allow grub2win to download the latest EFI package for your operating system.
  3. Ensure the target drive is the one the system boots into by default (usually C:\). Click Setup.
  4. Once it's done, click Return To The Setup Menu.
  5. Check “Delete setup files” if desired, and then Close The Setup Program.
  6. Grub2win will automatically scan for available operating systems. It will not find Batocera, unfortunately. Click Manage Boot Menu in the middle bottom of the window.
  7. Click Add New Entry near the top of the window.
  8. Under “Type”, select Custom code.
  9. Name the “Title” as “Batocera”, place it in whichever “Menu Slot” desired and reduce the “Pause Seconds” to 0.
  10. Click Edit Custom Code. A text document will be opened with the default text editor. Paste in the following and save the file:
     set efibootmgr=/EFI/BOOT/bootx64.efi
         getpartition  file  $efibootmgr  root
         if [ ! -z $reviewpause ] ; then
    	 echo GNU Grub will load the Batocera EFI Boot Manager at disk address $root
             g2wsleep  
         fi
         echo GNU Grub is now loading the Batocera EFI Boot Manager
         chainloader $efibootmgr
         savelast 1 'Batocera'

    Pleillear keeps an updated copy of the file at this Google Drive link, so check that if this page hasn't been updated for a while.

  11. Close the text editor.
  12. Grub2win will then scan the code for mistakes. If all goes well, click OK, followed by OK.
  13. Check that the Batocera listing is correct and in the menu slot desired. Then click Apply.
  14. Set any further cosmetic settings desired. Lower the “Grub timeout” from 30 down to 10 and change the background by clicking on the preview. When done, click OK.
  15. Grub2win will then install the desired boot menu onto the drive. Green means it's good. Click Close.
  16. Reboot and pray to whatever entity that you want that it worked.

You will likely have to wipe your hard drive's contents to do this, so no data can be carried over from a pre-existing Windows installation. To dual boot Windows and Batocera on the same drive:

  1. Partition your intended drive to begin with a large physical NTFS partition for Windows. It is recommended to use a GPT partition table. The rest of the free space will be used for Batocera.
  2. Install Windows via your preferred method. It will re-partition the existing NTFS partition into smaller logical partitions, but should retain its total size.
  3. In the empty space, add a new physical FAT32 partition 8 GB in size labelled “BATOCERA”. This will be used for Batocera's boot files.
  4. Immediately after the BATOCERA partition, create another partition to fill up the rest of the drive. This will be used as the “internal” userdata. Check out which filesystem to use. If you'd like to allow Windows to access the userdata partition, it is recommended to use exFAT or NTFS. BTRFS can also work, but in Windows it requires kernel drivers to be installed to allow access to it.
  5. Rename the folders in Windows' EFI partition from EFI/Boot to EFI/Boot_backup
  6. Download this ZIP file and extract it.
  7. Copy the contents of EFI_WINDOWS to Windows' EFI partition. The BOOT folder should be in the same spot as the old Boot folder was.
  8. Boot into Batocera from a USB drive, run blkid /dev/sda# (where sda# is the Windows EFI partition) and note down the ID of the partition.
    • FIXME (confirmation needed) To do this on Windows itself, open an administrator command prompt and run diskpart, list disk, select disk=# (where # is the number of the disk with Windows EFI on it, usually 0), uniqueid disk to get your disk ID (add the hyphen in the middle).
  9. Open ubuntu/grub.cfg and change 2AD8-4A0C to the ID of the partition.

The final grub.cfg file should look like this:

grub.cfg
set default=0
set timeout=5

menuentry 'Windows 10' {
  search --fs-uuid --no-floppy --set=root 2AD8-4A0C
  chainloader (${root})/EFI/Microsoft/Boot/bootmgfw.efi
}

menuentry "batocera.linux" {
  search --set=root --label BATOCERA
  linux /boot/linux label=BATOCERA console=tty3 quiet loglevel=0 vt.global_cursor_default=0
  initrd /boot/initrd.gz
}

Although Windows can be hostile towards other operating systems (erasing their bootloaders on an update, clearing the master boot record without warning, etc.), Macs can be even more hostile. Keep this in mind and definitely have a secure method of restoring a backup when playing with the Mac's bootloader.

For “Hackintosh” builds, this is usually safer.

Before installing rEFInd, be sure to read and understand the entire contents of its documentation first. Being negligent in this regard can result in an unbootable system if no flashing method is prepared earlier. To quote the author of rEFInd: “Note: I consider rEFInd to be beta-quality software! That said, rEFInd is a usable program in its current form on many systems.”

Install rEFInd Boot Manager and check that the system is still booting. Batocera might be automatically detected (but with a generic name); if so lucky you! Otherwise, Batocera can be added manually by adding the following to the refind.conf file.

menuentry "Batocera" {
    icon EFI/boot/icons/os_linux.png
    loader /boot/linux
    initrd /boot/initrd.gz
    options "label=BATOCERA console=tty3 quiet loglevel=0 vt.global_cursor_default=0"
}

Here are some examples on how to dual boot Batocera with popular Linux distributions like Ubuntu or Linux Mint.

Install Ubuntu

Follow your favorite method for the initial Ubuntu install, leaving extra unpartitioned space for Batocera and its userdata.

Batocera partitions

After the Ubuntu partition, create two consecutive partitions:

  • Partition 1: Type = fat32, name = BATOCERA
  • Partition 2: Type = ext4, no special labels or flags required, it must be created and placed right after the BATOCERA partition

Then download boot.tar.xz and unzip it on the BATOCERA partition.

Configure the Ubuntu GRUB

  1. While booted into Ubuntu, create /etc/grub.d/50_batocera with the following content:
    50_batocera
    #!/bin/bash
    
    cat << EOF
    menuentry "batocera.linux" {
          search --set=root --label BATOCERA
          linux /boot/linux label=BATOCERA console=tty3 quiet loglevel=0 vt.global_cursor_default=0
          initrd /boot/initrd.gz
    }
    EOF
  2. Run sudo update-grub
  3. Reboot

You will now be presented with the GRUB menu upon booting, allowing you to select either Batocera or Ubuntu to boot into.

Older versions of Ubuntu may need grub-customizer to do the above. More info on this earlier version of the page.

Alternatively, try the Linux Mint section below.

For other distributions like Linux Mint 19.03, you can use the following method. It also works for MX Linux, all mentions of Linux Mint also refer to MX Linux in this section.

Install Linux Mint

Follow your favorite method for the initial Mint install, leaving extra unpartitioned space for Batocera and its userdata.

Batocera partitions

Create 2 consecutive partitions on your hard drive:

  • Partition 1: type = fat32, name = BATOCERA
  • Partition 2: type = ext4. It must be created and placed right after the BATOCERA partition.

Then download boot.tar.xz and unzip it on the BATOCERA partition.

Since it's been set up manually, you can remove the autoresize flag from batocera-boot.conf. It may interfere with booting if it's still on and there's no more space to expand to.

Configure the GRUB boot loader

  1. Download the following file and save it to /etc/grub.d/15_batocera:
    15_batocera
    #! /bin/sh
    
    BATOCERA_UUID=$(lsblk --fs --noheadings --pairs -o TYPE,LABEL,UUID |
    		       grep -E '^TYPE="part" LABEL="BATOCERA" UUID="[^"]*"$' |
    		       sed -e s+'^TYPE="part" LABEL="BATOCERA" UUID="\([^"]*\)"$'+'\1'+ | head -1)
    
    if test -n "${BATOCERA_UUID}"
    then
        echo "Image batocera found on ${BATOCERA_UUID}" >&2
    
        cat <<EOF
    menuentry "batocera.linux" {
    	insmod fat
            search --no-floppy --fs-uuid --set=root ${BATOCERA_UUID}
    	linux /boot/linux label=BATOCERA console=tty3 quiet loglevel=0 vt.global_cursor_default=0
    	initrd /boot/initrd.gz
    }
    EOF
    fi
    • The file can also be automatically downloaded with the following command:
      sudo wget https://batocera.org/upgrades/grub/15_batocera -O /etc/grub.d/15_batocera
  2. Then run the following commands:
    sudo chmod a+x /etc/grub.d/15_batocera
    sudo update-grub

    Eventually, it will output the following:

      [...] 
    ​Image batocera found on 3377-44C4
      [...]
  3. Reboot

You will now be presented with the GRUB menu upon booting, allowing you to select either Batocera or Linux Mint to boot into.

https://www.ventoy.net/en/index.html

Technically, this isn't really dual-booting, but booting a static image already loaded onto your drive's filesystem as its own mounted filesystem. It can ease the process of updating the image, however this is probably unnecessary as Batocera itself has its own updating tool. Nonetheless it could be useful for machines that otherwise don't have an internet connection and have to rely on another one to update or machines that absolutely refuse to boot via conventional manners.

By default, Batocera's userdata partition is only 512MB before expanding, obviously not large enough to do anything. Ventoy's boot process prevents Batocera from seeing the drive as having any available free space, so auto-expansion on the first boot never occurs. This can be solved by either only mounting Batocera's boot partition (thus making the next immediate partition the userdata partition, whatever that may be) or by running the following (replace # with the number of GB you want in total, including the boot partition):

qemu-img resize batocera.img +#G
sudo losetup --find --show batocera.img

and expanding the userdata partition with Gparted or something similar.

If you want to keep using the command line for Gparted:

gparted /dev/loop *
  • dual_boot_ubuntu_batocera.linux.txt
  • Last modified: 3 months ago
  • by atari