Kobo Clara HD (kobo-clara)

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Kobo Clara HD
Insides
Insides
Manufacturer Kobo
Name Clara HD
Codename kobo-clara
Released 2018
Type ebook reader
Hardware
Chipset Freescale i.MX6 SLL
CPU 1x 1 GHz Cortex-A9
GPU PXP + EPDC
Display 1448x1072 6 inch eink/epaper
Storage Internal 8GB SD slot
Memory 512MB
Architecture armv7
Software
Original software Kobo Firmware
FOSS bootloader yes
postmarketOS
Category testing
Pre-built images no
Mainline yes
Unixbench Whet/Dhry score 213.3
Features
Flashing
USB Networking
Works
Internal storage
SD card
Battery
Works
Screen
Works
Touchscreen
Works
Multimedia
Camera Flash
Connectivity
WiFi
Works
NFC
Miscellaneous
FDE
Works
USB OTG
Works
HDMI/DP
Sensors
Magnetometer
Ambient Light
Proximity
Hall Effect
Haptics
Barometer


Contributors

Users owning this device

Warning

There seem to be different versions out there with different pmic setup, apparently even at the same i2c address, so make sure you know what you are doing. Approved board revisions are at least: 37NB-E60K00+4A4.

See pmaports#2356

The devicetree in the downstream kernel is imx6sll-e60k02.

For 37NB-E60K00+4B0 it is imx6sll-e60k02b00. There is now autodetection code in u-boot to sort that out, so no mixing up of 3.3V vs. 1.8V and similar regulators should happen.

Report anything else appearing in the wild.

Installation

An original Kobo Clara SD card or a copy (e.g. via dd) is recommended. The unpartitioned space at the beginning of the SD card contains the E-ink panel waveform information. This information is device specific and is copied to /lib/firmware/imx/epdc/epdc.fw on boot. See the original Pull Request for more information.

Replacing internal µSD

Internal µSD card can be replaced by something bigger.

A recommended practice to install software is to clone the SD card and keep the old one as backup or have at least the hidden waveform partition in place. before doing pmbootstrap install

So basically pull out µSD and connect to your PC and do: 

  dd if=/dev/sdX of=clara-backup.img

replace with something bigger (in reality only the waveform is needed but for simplicity) and do: 

  dd if=clara-backup.img of=/dev/sdX

and then use that sdcard with pmbootstrap install --sdcard

Hardware

Wireless

The Kobo Clara contains the Realtek RTL8189FTV, a 802.11bgn 2.4G single-chip solution. Using the mainline kernel this is supported by the RTL8189fs branch of this repo. Note this prints a lot of information to dmesg (prefixed with 'RTL871X').

Display

The Kobo Clara features "ComfortLight PRO" which allows you to adjust the brightness or temperature of your screen. This is supported in the mainline kernel under /sys/class/backlight which exposes backlight_warm and backlight_cold. The brightness can be adjusted by echoing a value (0 to 255) to brightness in these directories. 

   echo 10 | sudo tee /sys/class/backlight/backlight_warm/brightness

With mainline kernel, a drm interface is created, it should work out of the box, even textmode console should work. Waveform needs to be available before module is probed which might not be the case on first boot. With vendor kernel, only /dev/fb0 is created and special userspace is required to call vendor ioctls for refreshes.

USB

By default the USB port is in gadget mode. This enables rdnis (USB networking) and storage when plugged into a PC.

The USB can be changed to host mode, allowing a keyboard or storage to be plugged in. This requires a Micro USB OTG adapter. As root, you can change the USB role. 

   echo gadget > /sys/bus/platform/devices/ci_hdrc.0/role

Note: For some devices, external power may be required via the USB adapter.

UART

UART (3.3V) is available on J4. This is located near the edge of the PCB on the top right (with the USB at bottom). The default baudrate is 115200 (8N1). There is a second UART next to it (TP198)

Software

GUI support

Display servers

Xorg is recommended for now - Gnome Shell and at least some wlroots-based DMs share the issue described here

Display managers

TinyDM is recommended and just works.

GDM can work if you make it use Xorg (due to earlier mentioned Wayland bug).

SDDM (Xorg mode) does not seem to start.

SXMO

Recommended - for configuration details, see Using_ebook_reader_hardware

Device profile (WIP): 

export SXMO_DISABLE_LEDS="1"
export SXMO_MONITOR="Unknown-1"
export SXMO_POWER_BUTTON="1:1:gpio-keys"
export SXMO_SWAY_SCALE="2.5"
export SXMO_TOUCHSCREEN_ID="2"

Recommended to set Xorg DPI to 300.

AIR

Recommended - a set of customized scripts for AwesomeWM, the author uses them on a Clara HD. See here

Gnome

Runs but too heavy on CPU to work properly, when trying to do basic operations.

Plasma Desktop

Does not run, looks like it's short on RAM.

Other

Mobile DEs need to be tested, but they likely require GPU acceleration.

See also

Sources

Applications

Other

Almost identical device

  • Tolino_Shine_3 - this has the same board, uses the I.MX6 SoloLite SoC instead of the I.MX6 SLL, which has some subtle differences, like different version of the EPDC inside

Similar devices

  • Tolino_Shine_2HD_(tolino-shine2hd) - similar mainline status with above-mentioned kernel
  • Kobo Glo HD - will probably be in a similar state with above mentioned kernel if a devicetree is created
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