Requirements

You should have a USB Hub or similar with enough ports for

  • One LiveUSB
  • One USB Storage Device fast enough to run an OS from (e.g. SanDisk Ultra Fit); we shall call this the target device from here on.
  • One input device (USB keyboard and mouse required; for ease two ports recommended)

As well as a MacBook running a macOS version between El Capitan and High Sierra (inclusive).

You should be comfortable running commands on terminal; bash is assumed.

Caveats

  • Internal speaker and headphone jack output is still not working (probably).
  • Chaining GRUB2 bootloader probably needs to be manually (possibly automatable) rebuilt every kernel update, and probably the keyboard and touchpad drivers too.
  • Seems like installing GRUB2 adds a folder to the internal SSD’s EFI partition that may mess with the MacBook’s native bootloader’s bootable-partition discovery process and its BOOTCAMP bootloading process. This is not a major issue as
    • The bootloading process where one holds the Option key and chooses which volume to boot into still works fine,
    • Booting into Windows through GRUB2 is possible,
    • Removing the ubuntu folder from the EFI Partition, resetting the default boot partition to the macOS partition from within macOS, and not connecting the external drive containing Ubuntu should revert things to a normal state.
  • I strongly do not recommend installing Ubuntu to the internal drive as macOS upgrades tend to assume several things about the partitioning state of the internal SSD and messing around with it outside of Disk Utility and the Bootcamp-proscribed instructions may mess stuff up. In particular, note the upgrades beginning with Yosemite that converted HFS+ partitions so that they were within CoreStorage containers, and the upgrades beginning with High Sierra that converted HFS+ filesystems into APFS filesystems.

The Stages

  1. Preparing the LiveUSB.
    • After this stage you should have a USB containing a live image that you can boot into from your MacBook.
  2. Preparing the target device to make it bootable.
    • After this stage you should have a partition that your MacBook recognizes as a partition containing macOS that it can boot into.
  3. Installing Ubuntu to the target device.
    • After this stage you should have an Ubuntu installation in your target device that might not be bootable into.
  4. Installing the bootloader.
    • After this stage you should be able to boot into the Ubuntu installation, but keyboard and mouse support may not be present.
  5. Installing and configuring internal keyboard and touchpad drivers.
    • After this stage your Ubuntu should have internal keyboard and touchpad support, but it may no longer be bootable.
  6. Rebuilding and reinstalling the bootloader.
    • After this stage you should be able to boot into the Ubuntu installation and be able to use your mouse and keyboard.
    • This stage is similar to Stage 4, and I think it must be re-performed everytime you update the kernel of your installation.

Stage 1: Preparing the LiveUSB

  1. Download the Ubuntu 17.10 x86_64 Desktop image. I have not tried the other versions, which may have slightly different installation instructions in stage 3. The 17.10 Beta 2 desktop image suffices.
  2. We convert the .iso image file into a .dmg disk image file that the native bootloader recognizes as bootable. 
    hdiutil convert -format UDRW -o /path/to/img.dmg /path/to/image.iso
  3. We insert our Live-USB-to-be. Confirm the location that our LiveUSB-to-be is at with 
    diskutil list

    It should be identified by a name of the form diskN for some integer N. Then ensure that none of the partitions present on the disk are mounted with

    diskutil unmountDisk /dev/diskN
  4. We now burn the .dmg file to the disk with 
    sudo dd if=/path/to/img.dmg of=/dev/rdiskN

    Note that writing to rdiskN is speedier than writing to diskN as it skips several layers of software abstraction. Nevertheless, depending on the USB standard your LiveUSB supports, it may still take quite a while.

We are done with this stage. Unmount your LiveUSB.

Stage 2: Preparing the Target Device to Make It Bootable

  1. Insert the target device. Let diskN be its identifier; as before, we may discover its identifier with diskutil list.
  2. Erase the disk, write a GPT and EFI partition and a Journaled HFS+ partition to it with 
    diskutil eraseDisk JHFS+ Ubuntu GPT diskN
  3. Split the JHFS+ partition into a 128MB (size is pretty arbitrary; ex. we have used MB and not MiB) partition for the GRUB2 bootloader and a partition for our installation with a command like 
    diskutil splitPartition diskNs2 2 JHFS+ "Ubuntu Boot Loader" 128M ExFAT "Ubuntu" R
  4. We now mount the “Ubuntu Boot Loader” partition and navigate our terminal shell into its root; the standard Finder mounting suffices, whereupon it will be located at /Volumes/Ubuntu Boot Loader.
  5. We create the necessary folders necessary for the MacBook to recognize it as a macOS installation 
    mkdir mach_kernel
mkdir -p System/Library/CoreServices
  6. We create a .plist text file at System/Library/CoreServices/SystemVersion.plist with the contents 
    <xml version="1.0" encoding="utf-8"?>
<plist version="1.0">
<dict>
    <key>ProductBuildVersion</key>
    <string></string>
    <key>ProductName</key>
    <string>Linux</string>
    <key>ProductVersion</key>
    <string>Ubuntu Linux</string>
</dict>
</plist>
  7. Finally, we set the Apple-specific boot flag for the partition with 
    sudo bless --device /dev/diskNsM

    where M is the partition identifier of the “Ubuntu Boot Loader” partition, which can be discovered with diskutil list.

We are done. Insert the LiveUSB and shutdown or restart the MacBook.

Stage 3: Installing Ubuntu

We assume that the LiveUSB and the target device are both plugged in, and that the reader shall connect external input devices whenever required for input.

  1. When the MacBook starts, immediately during or before the bootup chime, hold down the Option button to enter the native bootloader. Select any of the “EFI Boot” options.
  2. You should boot into the LiveUSB’s GRUB2 bootloader. Select “Try Ubuntu without installing”. Your internal keyboard still works in the GRUB2 bootloader
  3. You should arrive at the Live Ubuntu desktop. You should need an external keyboard and mouse while in this environment. Proceed with installation as per usual, except for the following part.
  4. At “Installation type”, and presented with where and how on the disks you wish to install Ubuntu, select “Something else”. I do not like connecting to the Internet and updating just yet; we may do that later.
  5. Select to format the partition that was diskNsM in macOS as ext4, and use it as the root / mount point. Choose to install the bootloader in the same partition, that is, the partition that was diskNsM in macOS. Leave every other partitions and drives alone.
  6. Proceed and complete the installation, but do not reboot just yet.

Stage 4: Making Ubuntu bootable

You should now be booted into a Live Ubuntu OS. You should have both the LiveUSB connected from which you are running the OS, and also have your target device connected. We shall identify the partition that you have installed Ubuntu 17.10 to by sdAN where A is some small-caps letter and N is some integer.

We now build the GRUB2 bootloader.

  1. We mount the Ubuntu 17.10 partition. It suffices to use GNOME’s default mounting, whereupon it will be availabe at some location like /media/ubuntu/some_uuid_string/
  2. We bind our Live Ubuntu’s special files so that they are available when we chroot into our Ubuntu 17.10 installation with 
    cd /media/ubuntu/some_uuid_string/
sudo mount -B /dev dev
sudo mount -B /dev/pts dev/pts
sudo mount -B /proc proc
sudo mount -B /sys sys
sudo mount -B /run run
  3. We chroot into our Ubuntu 17.10 installation with 
    sudo chroot .
  4. We configure GRUB2 with 
    grub-mkconfig -o boot/grub/grub.cfg
  5. We build GRUB2 into a boot.efi located (for convenience) at the root of our Ubuntu 17.10 installation with 
    grub-mkstandalone -o boot.efi -d usr/lib/grub/x86_64-efi -O x86_64-efi --compress=xz boot/grub/grub.cfg
  6. From outside the chroot‘d shell (that is, from the Live Ubuntu desktop), save your boot.efi file somewhere from your macOS installation (e.g. Google Drive).
  7. Reboot into macOS. Due to how the native bootloader searches for bootable partitions, from now on you may have to always hold down the Option button and select the location you would like to boot into, else you may arrive at a GRUB2 fallback shell.
  8. Mount the “Ubuntu Boot Loader” partition. From the Terminal, (since Finder glitches out in that directory) copy the GRUB2 image into the partition with 
    cp /path/to/boot.efi "/Volumes/Ubuntu Boot Loader/System/Library/CoreServices/"
  9. It does not seem likely, but you may have to re-bless the “Ubuntu Boot Loader” partition.

We are done. Your Ubuntu 17.10 installation should now be bootable.

Stage 5: Building, configuring, and installing the keyboard and touchpad drivers

You do not need the LiveUSB from here on. Reboot the MacBook with Option key held down while booting, and select “Ubuntu Boot Loader”. You should boot into GRUB2, and should be able to select an Ubuntu menu entry to boot onto your Ubuntu 17.10 installation. From here on you may need to perform input via an external keyboard and mouse. Log in.

  1. Connect to the Internet.
  2. Update your package lists and then update your system (upgrade) with 
    sudo apt update

    and then

    sudo apt upgrade

    You may be prompted to restart your system, but it is important not to just yet.

  3. Install git and the build tools you will need with 
    sudo apt install git build-essential
  4. Download the experimental keyboard and touchpad drivers with 
    git clone https://github.com/roadrunner2/macbook12-spi-driver
  5. Build the drivers as kernel modules 
    cd macbook12-spi-driver
git checkout touchbar-driver-hid-driver
make
  6. Install the kernel modules 
    sudo mkdir /lib/modules/`uname -r`/custom/
sudo cp applespi.ko appletb.ko /lib/modules/`uname -r`/custom/
sudo depmod
  7. Write a configuration file to set the touchpad to an appropriate DPI. The file should be located at /etc/udev/hwdb.d/61-evdev-local.hwdb and its contents should be 
    # MacBookPro13,* (Late 2016), MacBookPro14,* (Mid 2017)
evdev:name:Apple SPI Touchpad:dmi:*:svnAppleInc.:pnMacBookPro13,1:*
evdev:name:Apple SPI Touchpad:dmi:*:svnAppleInc.:pnMacBookPro13,2:*
evdev:name:Apple SPI Touchpad:dmi:*:svnAppleInc.:pnMacBookPro14,1:*
evdev:name:Apple SPI Touchpad:dmi:*:svnAppleInc.:pnMacBookPro14,2:*
 EVDEV_ABS_00=::96
 EVDEV_ABS_01=::94
 EVDEV_ABS_35=::96
 EVDEV_ABS_36=::94

evdev:name:Apple SPI Touchpad:dmi:*:svnAppleInc.:pnMacBookPro13,3:*
evdev:name:Apple SPI Touchpad:dmi:*:svnAppleInc.:pnMacBookPro14,3:*
 EVDEV_ABS_00=::96
 EVDEV_ABS_01=::95
 EVDEV_ABS_35=::96
 EVDEV_ABS_36=::95
  8. We configure the modules to load on boot with 
    sudo su
echo 'add_drivers+="applespi intel_lpss_pci spi_pxa2xx_platform appletb"' >> /etc/initramfs-tools/modules
update-initramfs -u

You should now have a system that should load the drivers upon boot. But (I’m unsure about this point) you may have to rebuild your GRUB2 bootloader to correctly identify the kernel to boot into.

Stage 6: Rebuilding the GRUB2 Bootloader

After every system update (upgrade) that rebuilds the kernel, you should re-run this step.

  1. Reconfigure GRUB2. 
    sudo grub-mkconfig -o /boot/grub/grub.cfg
  2. Rebuild GRUB2 
    sudo grub-mkstandalone -o /boot.efi -d /usr/lib/grub/x86_64-efi -O x86_64-efi --compress=xz /boot/grub/grub.cfg
  3. Upload boot.efi to some place accessible by macOS.
  4. Reboot into macOS.
  5. Mount “Ubuntu Boot Loader” and replace the old boot.efi file in that partition with the new boot.efi file. Remember that it must be done with the Terminal as Finder glitches out.
  6. I doubt this must be done, but you may need to re-bless the partition.

Acknowledgments

  • Nailen Matschke (nailen@caltech.edu) for instructions on how to boot into Ubuntu from Apple’s native bootloader via intermediately booting into a standalone GRUB2 bootloader.
  • github.com/chisNaN for easy instructions to install and configure the keyboard and touchpad drivers.