Installing Lubuntu in Chuwi Hi10 Pro

In this guide, I will try to explain all processes I followed to have a working Lubuntu 17.10 in a Chuwi Hi10 Pro tablet. I hope this will be easily adapted to other Linux flavours.

This is the current state of my system:

Motivation

I wanted to replace my old and really used ASUS EeePC netbook with a newer and relative inexpensive machine, but it turned to be a really harsh task. Finally, I spoted Intel Cherry Trail tablets and I decided to give them a try with Linux. So I bought this one from a chinese reseller because it is cheap and it has good hardware.

Disclaimer

Some of the processes described in this guide are dangerous and can damage your device or void it's warranty, so follow this guide on your own risk!

Hardware

It seems that Chuwi manufactured two slightly different tablets under the name of Chuwi Hi10Pro. You can distinguish which one you have by looking at serial number:

• Version 1: Before serial number Hi10 PQ64G42160905000 (included)
• Version 2: After serial number Q64G42160905000

This will be important for some of the configurations we will need to perform later, but it is something really important if you want to perform any kind of factory reset, like flashing BIOS or any of the OSs that come preinstalled. You can find the original files and tutorials of how to do so in Chuwi official forums.

All this guide has been tested using a version 2 Chuwi, so maybe some of the configurations shown in this guide could not work in other tablets.

My Chuwi is loaded with:

Installing base system

I didn't want to mess arround with the SOs installed in the internal memory of my tablet, so I finally decided to install Lubuntu in a USB stick and boot from there using the USB hub built into the keyboard. This way, I could also mess arround with my installation with no worries, the warranty of my tablet will not be voided, and I also will be able to boot other computers with the same dongle.

So I used a VM (VirtualBox) to install Lubuntu into my USB stick. I created a new blank VM configured for Linux with no virtual hard disk drives attached. It is very important to enable EFI support, because the Chuwi won't boot if Lubuntu is not installed in EFI mode. In VirtualBox, you can change this setting in Configuration > System > Enable EFI.

After that, I loaded Lubuntu 17.10 ISO (Lubuntu official download site) into virtual CD-ROM drive and started up my VM. I continued the installation with no problems.

This USB stick is ready to boot in pretty much every computer, but not in this Baytrail tablets, because they have a 32 bit UEFI. To address that, we need to get a bootia32.efi and place it inside EFI partition of our new USB stick. You can get one here thanks to John Wells and his Asus Transformer T1000.

The easiest way to include this new file into the EFI partition is to plug it in another computer, mount the EFI partition, download the file and copy it in place:

cd /tmp
wget https://github.com/jfwells/linux-asus-t100ta/raw/master/boot/bootia32.efi
sudo mount /dev/sdX1 /mnt
sudo cp bootia32.efi /mnt/EFI/BOOT
sudo umount /mnt

You can use lsblk to know what /dev/sdX1 partition is the one you are looking for.

So now we are ready to boot from our new USB stick. To force the tablet to boot from USB stick, you will need to enter the BIOS by pressing Del key while Chuwi logo is on screen during tablet boot.

First boot

With this new 32bit UEFI, you will be able to boot from the USB stick, but the screen will be in vertical mode. In order to work better while trying to fix everything, log in, and once in the desktop, open a terminal with Ctrl-Alt-t and type:

sudo xrandr --output DSI-1 --rotate right

This is also a good moment to install some common dependencies that will be needed to build drivers later on:

sudo apt-get install build-essential git

So let's try now to fix everything up.

HW Accelerated graphics

Accelerated graphics work out of the box, but if you try to, for example, play a youtube video, browser will get stuck. This is not due to video issues but sound issues, we will fix that later.

NOTE: If you want to, you can install Intel Accelerated Graphics driver update tool. I have notice a very little improvement in speed and screen fluency, but I have not measured it in any way, it is just subjective. If you are running your system from a USB stick, installing these drivers could cause graphic crashes if you try to use the USB stick in other systems.

NOTE 2: It seems that Intel is discontinuing this method of driver update as you can read here

This information is based on a guide published in slimbook.es

To install such drivers, we will need to trick Intel installer, because there is no official release for Ubuntu 17.10 (artful), so we will download a release for 17.04 (zesty) and trick the installer to think we have installed this version instead.

Let's download Intel installer for zesty:

cd /tmp
wget https://download.01.org/gfx/ubuntu/17.04/main/pool/main/i/intel-graphics-update-tool/intel-graphics-update-tool_2.0.6_amd64.deb

Let's also download dependencies:

wget http://es.archive.ubuntu.com/ubuntu/pool/main/p/packagekit/libpackagekit-glib2-16_0.8.12-1ubuntu5_amd64.deb
sudo dpkg -i libpackagekit-glib2-16_0.8.12-1ubuntu5_amd64.deb
sudo apt-get install fonts-symbola

Now let's trick the installer. First, make a backup of lsb-release:

sudo cp /etc/lsb-release /etc/lsb-release.backup
sudo nano /etc/lsb-release 

As you may think, modify this file:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=17.04
DISTRIB_CODENAME=zesty
DISTRIB_DESCRIPTION="Ubuntu 17.04"

Before installing the package, let's import GPG keys:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 611B903CAB97EA77
sudo apt-get update

Now we are ready to install the package and launch it:

sudo dpkg -i intel-graphics-update-tool_2.0.6_amd64.deb
sudo intel-graphics-update-tool

Installer will now pop up. Just install it as normal. Do not forget to restore lsb-release:

sudo mv /etc/lsb-release.backup /etc/lsb-release

Sound, speakers and headphone jack

This information has been recopiled from a issue opened in Daniel Otero's guide to adapt Arch Linux to the Chuwi Hi 10. You can read it here.

In order to make sound work, some ALSA configuration files need to be modified. You can download the fixed configuration files and install them as follows:

cd /tmp
wget https://raw.githubusercontent.com/plbossart/UCM/218f2a59bf886221319b3c8666818b8c4acafd40/bytcr_rt5651/HiFi.conf
https://raw.githubusercontent.com/plbossart/UCM/218f2a59bf886221319b3c8666818b8c4acafd40/bytcr_rt5651/bytcr_rt5651.conf
mv HiFi.conf /usr/share/alsa/ucm/bytcr-rt5651
mv bytcr_rt5651.conf /usr/share/alsa/ucm/bytcr-rt5651

After a reboot, headphone plug will be working, but speakers will not work. This is because a GPIO needs to be enabled. To do so, a kernel module needs to be modified. Orochimarufan published the patch to do so here. You need to make this modifications to the file sound/soc/codecs/rt5651.c placed inside your kernel source code directory and then rebuild and install the modified new kernel.

See Building a new kernel section on this guide to know how to get kernel source code, recompile and install it.

Automatic headphone plug detection is not working. So you will need to select which sound output you want to activate using desktop controls in LXDE taskbar.

Backlight

In order to make the backlight work, some kernel flags needs to be changed:

CONFIG_PWM=y
CONFIG_PWM_CRC=y
CONFIG_I2C_DESIGNWARE_PLATFORM=y
CONFIG_I2C_DESIGNWARE_PCI=y
CONFIG_INTEL_SOC_PMIC=y
CONFIG_DRM_I915=m

CONFIG_PWM_LPSS=y
CONFIG_PWM_LPSS_PCI=y
CONFIG_PWM_LPSS_PLATFORM=y
CONFIG_X86_INTEL_LPSS=y

See Building a new kernel section on this guide to know how to get kernel source code, and change configuration flags.

Some of these flags has been taken form Daniel Otero's guide to adapt Arch Linux to the Chuwi Hi 10. You can read it here. This was also featured on freedesktop site here.

I weren't able to make it work with kernel flags specified by Daniel, I finally needed to change some of the values, as I read here.

As you can read in this last quote, you can get/modify brightness configuration by reading/writing in /sys/class/backlight/intel_backlight/actual_brightness. Also you can read how to set up brightness after boot by adding it to initramfs. After kernel configuration change, brightness up and down fn keyboard key combinations will also work fine.

Touchscreen

NOTE: I am currently working on this. The screen is now detected, but it is imprecise and needs to be calibrated.

In order to get the screen working, screen firmware need to be installed. In this case, only one file will be needed:

cd /tmp
wget https://github.com/onitake/gsl-firmware/blob/master/firmware/chuwi/hi10_pro-z8350/silead_ts.fw?raw=true

The community has been extracting firmwares for this kind of touchscreens. You can get more information here. Notice that if you have the first version of the Chuwi Hi10 Pro, you must download a different silead_ts.fw!

Once the firmware is downloaded, it needs to be copied in the right place for the system to find it at startup:

cp silead_ts.fw /lib/firmware/silead

Once the firmware is placed, gslx680 drivers need to be installed, so let's download, build and install them:

cd /tmp
git clone https://github.com/onitake/gslx680-acpi
cd gslx680-acpi
make
sudo make install

/etc/modules will need to be changed, in order to let the system load the new module. This line needs to be added:

gslx680_ts_acpi

If the screen is not working properly after reboot, see /var/log/syslog for more details.

Volume hardware buttons and fn key combinations on keyboard

Volume hardware buttons are recognized by the system, if you run xev and press them, it shows that keypresses are indeed being detected. But in ~/.config/openbox/lubuntu-rc.xml wrong commands are binded to XF86AudioLowerVolume and XF86AudioRaiseVolume.

Almost every fn combination (blue icons on keyboard) are detected succesfully, but the have no binded action.

If you want to configure any of the fn key combinations, you can modify ~/.config/openbox/lubuntu-rc.xml to bind them to some script or command. You can also use xev to know the ID of the key/combination you are pressing.

Thanks to jamontes for his help in these issues.

Bluetooth

Bluetooth is working after installing drivers (big thanks to Larry Finger for this!):

cd /tmp
git clone https://github.com/lwfinger/rtl8723bs_bt
cd rtl8723bs_bt
make
sudo make install

Every time you need to activate bluetooth, a script must be run, so is a good idea to set a root cron job to do so at startup.

Create a new directory, copy contents in it:

sudo mkdir /opt/rtl8723bs/
sudo cp * /opt/rtl8723bs/
sudo crontab -e

Then write the cron job:

@reboot cd /opt/rtl8723bs/ && ./start_bt.sh 

Light sensor

The light sensor will work after installing drivers. These can be found here, Thanks to burzumishi for this!

cd /tmp
git clone https://github.com/burzumishi/linux-baytrail-flexx10/ -b Readme-stage --single-branch
cd linux-baytrail-flexx10/kernel/modules/cm3218_light_sensor
make
sudo make install
sudo modprobe cm3218

Once installed, you can read sensor value like this:

sudo cat /sys/bus/iio/devices/iio\:device1/in_illuminance0_input

Accelerometer and screen rotation

I have prepared a daemon for this task: bma250 screen autorotator

In order to rotate the touchscreen at the same time than the image, you will need to compile this program defining XDEVICE macro using the ID of your touchscreen provided by xinput list. In my case I needed to compile and install it like this:

autoreconf -vfi
./configure CFLAGS="-DXDEVICE=11"
make
sudo make install

Do not forget also to configure LXDE to run the program at startup.

Customizing and compiling Linux Kernel

NOTE: Compiling kernel is a CPU-intensive task, I recommend making the build step in a different (and more powerful) Ubuntu/Lubuntu machine. If you try to build the kernel in the Chuwi, it would take several hours (or days).

First of all, lets find out what version of Linux kernel is installed on the Chuwi:

uname -r

In my case it was 4.13.0-25-generic.

Now, we will need to download the kernel sources. Remember to verify you are downloading the correct kernel version obtained in the last step. Of course, you could build and install another kernel version if you want to.

apt-get source linux-image-4.13.0-25-generic

If you are running this commands in the same linux version you want to build and install, you could also refer to your kernel version like this:

apt-get source linux-image-$(uname -r)

If you are getting an error saying that no source could be found for this packages, make sure you have deb-src repositories activated in \etc\apt\sources.list. If they were disabled, do not forget to perform an apt-get update.

If you have not build a kernel in the system before, some more packages will be needed for the build:

sudo apt-get build-dep linux-image-4.13.0-25-generic

You will also need to install ncurses:

sudo apt-get install libncurses-dev

This is a good point to applly GPIO modifications in sound/soc/codecs/rt5651.c specified in "Sound, speakers and headphone jack" section. This is the patch for this specific kernel version adapted from Orochimarufan's file.

One of the main reasons building the kernel is necesary, is because some configurations need to be changed. In order to do so, some permissions need to be granted inside kernel source directory:

chmod a+x debian/rules
chmod a+x debian/scripts/*
chmod a+x debian/scripts/misc/*

Now is time to change this configurations, clean the project and edit the configuration:

fakeroot debian/rules clean
fakeroot debian/rules editconfigs

At this point, you will be prompted with several questions about if you want to edit the configurations associated to each kernel flavour. Normally you will want to modify the configuration for the generic kernel (amd64/config.flavour.generic).

When you agree to edit the configuration for a certain kernel flavour, you will get to a screen like this:

In this screen, press / key to search for all configurations that need to be changed (specified in blacklight section of this guide):

Select which one of the search results you want to change by pressing the number specified in each result:

In this case, I2C_DESIGNWARE_PCI does not have the correct value, so press 1 to return to configuration page and be able to change it's value:

In this screen is only necessary to press Y to include this feature:

You could also need to press N or M to change the value as desired.

For this kernel version, I only needed to change these configurations:

CONFIG_I2C_DESIGNWARE_PCI=y

CONFIG_PWM_LPSS=y
CONFIG_PWM_LPSS_PCI=y
CONFIG_PWM_LPSS_PLATFORM=y

The rest of them (complete list here) were already correct.

Do not forget to save the changes before selecting exit. After this, we will be asked once again if we want to change the configuration for the other kernel flavors.

Before building the kernel, let's change version name to be able to distinghish this new kernel from the older one once installed (or in GRUB for instance) and making it newer than the stock one. To do so, let's add a modifier to the first version number of debian/changelog:

Once all configurations are changed, build the kernel:

fakeroot debian/rules binary-headers binary-generic binary-perarch

If you are getting module error checks, you may want to build with skipmodule=true:

fakeroot debian/rules binary-headers binary-generic binary-perarch skipmodule=true

Several .debpackages must have been generated at this point. Just install them on the Chuwi:

dpkg -i *.deb

In the case you want to know all kernel packages you have installed, you can get a list of them:

dpkg -l | grep linux

License

This work is licensed under a Creative Commons Attribution 4.0 International License.