PocketBook 614 plus (pocketbook-614-plus)

From postmarketOS
PocketBook 614 plus
File:CHANGE ME TO DEVICE CODENAME.jpg
CHANGE_ME
Manufacturer PocketBook
Name 614 plus
Codename pocketbook-614-plus
Model PocketBook 614
Released 2017
Category testing
Pre-built images no
Original software PocketBook firmware
Original version Linux 3.0.8
postmarketOS kernel 6.8.0
Hardware
Chipset Allwinner A13
CPU ARM Cortex-A8 @ 1Ghz
GPU Mali 400 MP1
Display 800x600 e-paper
Storage microSDHC
Memory 256 MB
Architecture ARMv7
Type Ebook reader
Unixbench Whet/Dhry score 0.0
Features
USB Networking
Works
Flashing
Touchscreen
Display
WiFi
FDE
Mainline
Works
Battery
Works
3D Acceleration
Internal storage
Works
USB OTG
Sensors
Accelerometer
Magnetometer
Ambient Light
Proximity
Hall Effect
Barometer
Power Sensor
Misc
Memory Card
Works
FOSS bootloader
Works
U-Boot
Primary Bootloader
Works
Secondary Bootloader
Mainline
Works
Internal Storage
Works
SD card
Works
USB Host
USB Peripheral
Works
Display
Keyboard
Buttons


Contributors


Users owning this device


Original software

A regular sdcard is used as internal memory, so we can simply take it out and read/write it on the computer. It is worth noting that the image is tied to a specific sdcard (its serial number), but it is enough to simply untie the image from this dependence.

Note Note: Before experiments, make a backup copy of the SD card (via dd)

# fdisk -l /dev/sda

Disk /dev/sda: 7.37 GiB, 7908360192 bytes, 15446016 sectors
Disk model: Card  Reader    
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot   Start      End  Sectors   Size Id Type
/dev/sda1       1009664 15446015 14436352   6.9G  b W95 FAT32
/dev/sda2  *      73728   139263    65536    32M  6 FAT16
/dev/sda3             1  1009664  1009664   493M 85 Linux extended
/dev/sda5        139264   172031    32768    16M 83 Linux
/dev/sda6        172032   204799    32768    16M 83 Linux
/dev/sda7        204800   275455    70656  34.5M 83 Linux
/dev/sda8        275456   776191   500736 244.5M 83 Linux
/dev/sda9        776192   976895   200704    98M 83 Linux
/dev/sda10       976896  1009663    32768    16M 83 Linux

Partition table entries are not in disk order.
sda1 - userdata
sda2 - boot partition (with kernel)
sda5 - ???
sda6 - ???
sda7 - root (/)
sda8 - /ebrmain (contain cramfs.img)
sda9 - /mnt/secure (contain some apps and libs)
sda10 - ??? (contain dictionaries)

Unlinking an image from a specific SD card: after the system starts, the main application is launched - pocketbook located in /dev/sda8 (in fact, this is a link to /mnt/cramfs/bin/monitor.app). This binary contains a check for the serial number of the memory card. However, we can easily cheat this check: replace the path to the serialnumber of sdcard with a simple text file with this number.

copy the cramfs.img file from sda8 and unpack it: cramfsck -x tmp_cram cramfs.img As a result, there will be a monitor.app file in the tmp_cram/bin directory. Using strings we can find that the program gets the serial number from /sys/block/mmcblk%c/device/serial Сreate a file with serial number in /mnt/secure (you can do it in another place, the main thing is that the final path is the same length as the line above) and replace path from from /sys/block/mmcblk%c/device/serial to your file. now just copy the file to sda8, delete the old link and create a new one. ln -s monitor_patched.app pocketbook

Installation

pmbootstrap install --sdcard=/dev/sda

See also