Ubuntu Touch

Official website

Making the root partition read-write

Enable temporarily

Open "System Settings"
In "About" enable "Developer Mode"
Install "UT Tweak Tool" from OpenStore
Open "UT Tweak Tool"
In the menu (top-left) select "System"
In "Make image writable" select "[Read-Write]"

I do not recommend enabling this permanently. You should probably add individual writable directories

SSH Access

Open "System Settings"
In "About" enable "Developer Mode"
Install "UT Tweak Tool" from OpenStore
Open "UT Tweak Tool"
In the menu (top-left) select "System"
In "SSH Settings" enable SSH access

Installing packages

Make the root partition read-write
Run sudo apt update
Install using sudo apt install (package)

Create writable directories in root

Make the root partition read-write
Run sudo nano /lib/systemd/system/(service name, arbitrary).mount
Enter the following:

[Unit]
Before=local-fs.target

[Mount]
Where=(target location)
What=/userdata/system-data/(target location)
Type=none
Options=bind

[Install]
WantedBy=local-fs.target

Run sudo systemctl enable (service name)
Run sudo systemctl start (service name)

Changing the desktop environment

Note: many Ubuntu Touch ports do not have DRM support, so a lot of DEs will not work

Make the root partition read-write
Run sudo systemctl stop lightdm
Run sudo systemctl disable lightdm
Run sudo nano /lib/systemd/system/desktop.service
Enter the following:

[Unit]
Description=User Session Starter
Conflicts=getty@tty7.service plymouth-quit.service
After=systemd-user-sessions.service getty@tty7.service plymouth-quit.service

[Service]
ExecStart=/usr/bin/su phablet -c (session command e.g. startx)
Restart=always

[Install]
WantedBy=graphical.target

Run sudo systemctl enable desktop
Run sudo systemctl start desktop

Setting up startx

Make the root partition read-write
Install xinit
Set up your .xinitrc
Edit /etc/X11/Xwrapper.config
Change allowed_users=console to allowed_users=anybody

The screen turns off after a minute

To fix permanently

Make the root partition read-write
Run sudo rm /lib/systemd/system/lightdm.service

The screen does not update when running an X11 WM

To update the screen once run: cat /sys/class/graphics/fb0/modes > /sys/class/graphics/fb0/mode (as root)

To fix permanently

Make the root partition read-write
Run sudo nano /lib/systemd/system/fb-refresher.service
Enter the following:

[Unit]
Description=Fix the screen

[Service]
ExecStart=/usr/bin/sh -c "while [ ! ]; do cat /sys/class/graphics/fb0/modes > /sys/class/graphics/fb0/mode; done"

[Install]
WantedBy=multi-user.target

Run sudo systemctl enable fb-refresher
Run sudo systemctl start fb-refresher

Enable swap

Enable temporarily

Run sudo dd if=/dev/zero of=/userdata/swapfile bs=1024 count=(desired size in kilobytes) status=progress
Run sudo chmod 600 /userdata/swapfile
Run sudo mkswap /userdata/swapfile
Run sudo swapon /userdata/swapfile

Enable permanently:

Make the root partition read-write
Run sudo nano /lib/systemd/system/swap.service
Enter the following:

[Unit]
Description=Enable swap

[Service]
Type=oneshot
ExecStart=/usr/sbin/swapon /userdata/swapfile
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

Run sudo systemctl enable swap
Run sudo systemctl start swap

Installing nix and home-manager

Installing nix:

Create /nix
Install curl
Install xz-utils
Disable writable root
Run sudo chown -R phablet /nix
Run sh <(curl -L https://nixos.org/nix/install) --no-daemon

You might get ERROR: ld.so: object 'libtls-padding.so' from LD_PRELOAD cannot be preloaded. It can be safely ignored. To disable this warning:

Add unset LD_PRELOAD to the end of ~/.bashrc

Installing home-manager:

Follow the home-manager standalone guide

TheMasterArchiver