SAMSUNG xe303c12

Hardware

Hardware Model
CPU Samsung Exynos 5250 AEON
eMMC SanDisk SDIN7DU2-16G NAND Flash
RAM DDR3L-1600 , 8xELPIDA J2108EDBG-GN-F (2Gbx8)
Power Controller MAX 77686 EWE 1237
PMU TPS65090 TI 291
Embeded Controler STM32F100R8
Trusted platform module Infineon SLB9635
SPI Flash Winbond 25Q32DSWIG
WiFi/Bluetooth Murata SS2907002
PCI clock PI6C557-03
Audio codec MAX98095

Booting Linux

This is chapter copied from Source

Switch to developer mode

  1. Turn off the laptop.
  2. To invoke Recovery mode, you hold down the ESC and Refresh keys and poke the Power button.
  3. At the Recovery screen press Ctrl-D (there's no prompt - you have to know to do it).
  4. Confirm switching to developer mode by pressing enter, and the laptop will reboot and reset the system. This takes about 15-20 minutes.

Note: After enabling developer mode, you will need to press Ctrl-D each time you boot, or wait 30 seconds to continue booting.

Enable booting from external storage

  1. After booting into developer mode, hold Ctrl and Alt and poke the T key. This will open up the crosh shell.
  2. Type shell to get into a bash shell.
  3. Type sudo su to become root.
  4. Then type this to enable USB booting:
     crossystem dev_boot_usb=1 dev_boot_signed_only=0
    
  5. Reboot the system to allow the change to take effect.

Create a root USB or SD for dual booting

These instructions are written for installing to a USB drive with the sda device, assuming no other USB drives are plugged in. For an SD card, click here to magically adjust the instructions for the mmcblk1 device that an SD card will register as.

  1. Get a root shell as described in the previous section.
  2. Since ChromeOS will automatically mount any partitions it finds, unmount everything now:
    umount /dev/sda*
    
  3. Start fdisk to create a GPT partition table:
    fdisk /dev/sda
    
  4. At the fdisk prompt:
    4.1. Type g. This will create a new empty GPT partition table.
    4.2. Write the partition table and exit by typing w.

  5. Partition the micro SD card:

    cgpt create /dev/sda
    cgpt add -i 1 -t kernel -b 8192 -s 32768 -l Kernel -S 1 -T 5 -P 10 /dev/sda
    
  6. To create the rootfs partition, we first need to calculate how big to make the partition using information from cgpt show. Look for the number under the start column for Sec GPT table which is 15633375 in this example:

     localhost / # cgpt show /dev/sda
            start        size    part  contents
                0           1          PMBR
                1           1          Pri GPT header
             8192       32768      1   Label: "Kernel"
                                       Type: ChromeOS kernel
                                       UUID: E3DA8325-83E1-2C43-BA9D-8B29EFFA5BC4
                                       Attr: priority=10 tries=5 successful=1
    
         15633375          32          Sec GPT table
         15633407           1          Sec GPT header
    
  7. Replace the xxxxx string in the following command with that number to create the root partition:
    cgpt add -i 2 -t data -b 40960 -s `expr xxxxx - 40960` -l Root /dev/sda
    
  8. Tell the system to refresh what it knows about the disk partitions:
    sfdisk -R /dev/sda
    
  9. Format the root partition:
    mkfs.ext4 /dev/sda2
    
  10. Download and extract rootfs tarball:
    cd /tmp
    wget http://archlinuxarm.org/os/ArchLinuxARM-peach-latest.tar.gz
    mkdir root
    mount /dev/sda2 root
    tar -xf ArchLinuxARM-peach-latest.tar.gz -C root
    
  11. Flash the kernel to the kernel partition:
    dd if=root/boot/vmlinux.kpart of=/dev/sda1
    
  12. Unmount the root partition:
    umount root
    sync
    
  13. Reboot the computer.
  14. At the splash screen, instead of pressing Ctrl-D to go to CromeOS, press Ctrl-U to boot to the external drive.
  15. After logging in as root (password is "root"), you can connect to a wireless network by running:
    wifi-menu
    

Enable debuging mode

There is possible to disable rootfs protection and even change files in such directories as /etc. Download this tool Recovery utility create usb/sd with recover image. Then boot to restore your chromebook and while setting up choose debuging mode.

Disabling updates

As with newer version ChromeOS becomes less usable and slower here is option to disable update service.

initctl stop update-engine

Recovery mode

Press ESC + Refresh buttom and then press Power button

Links

  1. https://archlinuxarm.org/platforms/armv7/samsung/samsung-chromebook
  2. https://www.ifixit.com/Teardown/Samsung+Chromebook+Series+3+Teardown/12225
  3. http://www.slideshare.net/jjwu6266/introducing-samsung-chromebookxe303
  4. http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00251732.pdf
  5. http://www.infineon.com/cms/en/about-infineon/press/press-releases/2009/INFCCS200912-015.htm
  6. https://www.pericom.com/assets/Datasheets/PI6C557-03.pdf
  7. https://datasheets.maximintegrated.com/en/ds/MAX98095.pdf
  8. https://chrome.google.com/webstore/detail/chromebook-recovery-utili/jndclpdbaamdhonoechobihbbiimdgai?hl=en
  9. https://www.reddit.com/r/chromeos/comments/3t96gw/how_to_stop_chromebook_from_updating/