Group: Hardware/Computers/e-readers/Kobo/Aura H2O Edition 2

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Revision as of 12:03, 18 June 2018 by GNUtoo2 (talk | contribs) (→‎Serial/UART)
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External interfaces

USB

Several interfaces are exposed through USB:

  • It's possible to make the device switch to fastboot during boot
  • If the device is not registered, you can switch to mass-storage by selecting "no wifi" during the device boot.

Power button

Touchscreen

Internal interfaces

Serial/UART

Voltage 3.3v
Baudrate 115200
Settings 8N1 (the default almost everywhere)

To get a shell you can login through the serial port with the user 'root': 

(none) login: root
[root@(none) ~]#

However once logged the console will probably freeze at some point. This is because the device has aggressive power management which makes the device goes into suspend.

To wake up the device, touching the screen is enough, however touching the screen all the time is not very convenient for development.

It seems to be an userspace application that makes the device goes into suspend. So we will overwrite /sys/power/state with a file that does nothing. We have ram filesystem mounted in /tmp, so we will use that to be saver (as it will not make permanent modifications): 

[root@(none) ~]# mount
[...]
none on /tmp type tmpfs (rw,relatime,size=16384k)
[...]

We can overwrite /sys/power/state like that: 

[root@(none) ~]# touch /tmp/state
[root@(none) ~]# mount -o bind /tmp/state /sys/power/state

This effectively prevent the device from going into suspend.

PCB

Here are the chips on the top of the PCB. Caevats:

  • you need a big screen to view properly the markings as it will line-break with smaller screens
  • The markings might contain errors as they are tiny and some letter/number could be mixed up
  • I didn't disassemble it enough to see the bottom because the connectors seemed really fragile (they even had glue inside them) so if I do, I fear that I won't be able to put everything back in place. There might be some more chips on the bottom.
Usage Location Package Markings Driver(s) Documentation
512M RAM 168-Ball PoP-FBGA 
NANYA 1718
NT6TL 128M 32BQ-G0
7201166 AEP 3TW
?
? ? 
SEC 737
BO41
KLM8616EME
H56P4788D
?
System on a chip ? (BGA) 
MCIMX6V7DVN10AB
XAA 1739
TAIW HMAAXK
Lots of drivers
WiFi chip (and potentially other features) ? 
REALTEK
8189PTY
H857492
GH438
?
? ? 
RICOH AC5T619
1137
7409N1
Power management integrated circuit (and potentially other features) ? 
TPS
65185
T1 7AI
CS6S G4
?
On the display flex cable ? 
TT21000
-48L0I
1725 B03
PRD627959
PHI   □ C
041
?

Pictures

Some pictures of the top PCB taken with a camera:

Software

Kobo software

Stock OS analysis

  • The default OS forces the user to register or use some network services like Kobo, google, facebook, etc

Source code

Linux sources analysis

The sources have multiples boards selected: 

CONFIG_MACH_MX6Q_ARM2=y
CONFIG_MACH_MX6SL_ARM2=y
CONFIG_MACH_MX6SL_EVK=y
CONFIG_MACH_MX6SL_NTX=y
# CONFIG_MACH_MX6Q_SABRELITE is not set
CONFIG_MACH_MX6Q_SABRESD=y

However there is a gen_bootimg.sh with inside: 

./mkbootimg --kernel arch/arm/boot/zImage --ramdisk uramdisk.img --base 0x80800000 --cmdline "console=ttymxc0,115200 init=/init androidboot.console=ttymxc0 max17135:pass=2, fbmem=6M video=mxcepdcfb:E060SCM,bpp=16 no_console_suspend" --board evk_6sl_eink -o boot.img

This seem to indicate that the file describing the e-reader hardware is arch/arm/mach-mx6/board-mx6sl_evk.c (along with arch/arm/mach-mx6/mx6sl_evk_pmic_pfuze100.c)

The source code of this file seem to be derived from a single board computer from Freescale/NXP, but it is odd as some features not present in this e-reader hardware aren't disabled at compilation time.

Firmwares

Since Linux and u-boot sources are available, the most interesting information (for RYF certification) to look for is if some peripherals require a non-free firmware. The most common places where firmwares can be used or required are:

  • The WiFi/bluetooth driver
  • The touchscreen driver

It might also be a good idea to double check that the e-paper display only needs some calibration data and doens't require any nonfree firmware

GPU

According to the linux compilation configuration the GPU is unused: 

#
# MXC Vivante GPU support
#
# CONFIG_MXC_GPU_VIV is not set

WiFi

The WiFi chip seem to use an out of tree driver: 

CONFIG_WLAN=y
# CONFIG_USB_ZD1201 is not set
# CONFIG_WIFI_CONTROL_FUNC is not set
# CONFIG_BCM4329 is not set
# CONFIG_BCMDHD is not set
# CONFIG_HOSTAP is not set

This will need a bit more research to get some confirmation on that

Boot logs

Manufacturer informations

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