After installing

What to know once Linux runs on the tablet: the first start, switching between Android and Linux, updates, more systems on the card, how to remove Linux again, and where to look when something is wrong. The install itself is in Installing Linux.

First start#

The Lenovo logo, then a text summary on the panel, then the desktop. The first start takes a little longer (the root grows to fill the partition); after that the desktop is up about 12 s after the kernel starts. GNOME logs you in automatically.

Wi-Fi: top right → Wi-Fi → pick your network → a notification asks for the password. Until then the clock is wrong (Android keeps the real time in a place Linux cannot read); it sets itself once the network is up. The time zone comes from the PC you built on. A Wi-Fi icon with a ? means the internet check failed; it usually clears within a minute.

In GNOME's Terminal:

uname -r                                # the release kernel
systemctl is-system-running             # running, or degraded (see systemctl --failed)
cat /etc/tb323fu/android-boot.sha256    # the hash the script printed in the wayback step

Then try the way back to Android and back to Linux once, while you are at the desk (next section).

In mainline Linux the power button alone does not force the tablet off; hold power + volume down.

Switching between Android and Linux#

The tablet boots whatever is in boot_a. Android's boot image is kept in boot_b; switching copies one or the other into boot_a and restarts. Every way below checks hashes before and after writing and stops without restarting on a mismatch. How it works: android/README.md.

A switch takes about 40 s. If the Linux image that ran last is a kernel still on trial (below) or one that failed, the Switch to Linux module writes the last confirmed kernel instead and says so.

From a PC

Direction	How	Checked
from a PC, Linux running	tools/flash-boot.sh over SSH (USB network: tablet 192.168.7.2, PC 192.168.7.1)	yes
from a PC, through Android	tools/cycle.sh: back to Android if needed, write boot_a over adb, reboot, wait for SSH	yes, many times

If neither way works: Recovery (EDL with your own backup from rooting).

Updates#

Kernel. Open Device Helper → About → Kernel Updates, or tb323fu-ctl kernel update. The helper checks the project's GitHub Releases once a day (it only checks; downloading and installing are your choice) and packs the new kernel into your own stock boot image from boot_b. The channel is stable by default: it offers the newest release that is not a pre-release (kernel-t40 at the time of writing); testing offers pre-releases too. A kernel from a file you built: Install Kernel from File… (custom-kernel.md).

Trial and Keep. A new kernel is first on trial. Before writing it, the helper saves the running one as linux-good.img. On the stable channel the kernel is confirmed by itself once the system has been up for 90 s. On the testing channel, for pre-releases and for kernels from a file, only Keep (in the app, or tb323fu-ctl kernel keep) confirms it. A kernel that is not confirmed by its third start is replaced by linux-good.img and the tablet restarts. A kernel that dies before the initramfs runs cannot be caught this way; then the way back is EDL (recovery). Details: helper.md → Kernel updates.

Helper. Releases tagged helper-vX.Y.Z (helper-v0.4.1 is the current stable one) show in About → Helper Updates and in tb323fu-ctl helper. Who installs them depends on who installed the helper (helper.md → Helper updates):

On other systems Open Device Helper shows the command when a package manager owns the helper.

The distribution updates the usual way (apt, pacman, nixos-rebuild, …). The kernel and its modules come with the boot image, not from the distribution's packages.

Optional: the project's Mesa for Vulkan and OpenCL#

After the install, every application uses the distribution's Mesa, and nothing changes that by itself. The project also offers its own Mesa build for this GPU — Turnip (Vulkan) and rusticl (OpenCL) — which is much faster for GPU compute (OpenCL programs, Vulkan compute; on this tablet Geekbench 7 OpenCL about 20000 instead of about 7500). OpenGL and the desktop itself keep using the distribution's Mesa either way. It is optional and comes as a binary release only.

The scores were measured on one tablet (the author's) and are for orientation only; yours may differ.

• Try it: Open Device Helper → Performance → Graphics Drivers → Check Now, then Download and Install…, and switch on Use the Project's Mesa; or tb323fu-ctl mesa update and tb323fu-ctl mesa on. It is used by applications started after the next login. The distribution's Mesa stays installed next to it.
• On trial: a version you switch on has to be confirmed with Keep (the banner on the Performance page, or tb323fu-ctl mesa keep). Without Keep, the third start switches back to the distribution's Mesa by itself.
• Going back: switch it off (tb323fu-ctl mesa off, used from the next login), or Go Back… to the previously installed version.
• One program only: tb323fu-mesa run COMMAND runs one program with the project's Mesa and tb323fu-mesa distro COMMAND with the distribution's, whatever the setting — handy for comparing, or when one application misbehaves.

Details, and using a release without the helper: helper.md → Graphics drivers. Measured results: Performance → GPU.

Another system on the card#

Each system lives in its own partition, and all of them share the one kernel in boot_a. The guided script puts one system on the card; more are added by hand: a partition named tb323fu-<name> in the card's free space and a root built into it (Installing by hand, steps 4–5). Which systems have been tried and how each one is built: Distributions. Picking one: Open Device Helper → Systems, or tb323fu-ctl boot (Installing by hand → Multiboot).

Removing Linux#

Linux never replaces Android: Android's data, apps and system stay as they were (unless you moved the Linux root to the internal storage, last row). Going back to the stock tablet, in this order:

Never restore a partition table backup taken before a firmware update over a newer layout, and never restore another tablet's table: the backup contains your device's unique GUIDs. A complete factory state (which wipes the tablet): Recovery → Full reinstall.

Something is wrong#

Anything else: open an issue on GitHub with what you did and what you saw.