This page contains information about the Samsung Chromebook 2 that is interesting and/or useful to software developers. For general information about getting started with developing on Chromium OS (the open-source version of the software on the Chrome Notebook), see the Chromium OS Developer Guide.
Caution: Modifications you make to the system are not supported by Google, may cause hardware, software or security issues and may void warranty.
An unrelated note: Holding just Refresh and poking the Power button hard-resets the machine without entering Recovery. That‘s occasionally useful, but use it with care - it doesn’t sync the disk or shut down politely, so there's a nonzero chance of trashing the contents of your stateful partition.
Enabling Developer mode is the first step to tinkering with your Chromebook. With Developer mode enabled you can do things like poke around on a command shell (as root if you want), install Chromium OS, or try other OS's. Note that Developer mode turns off some security features like verified boot and disabling the shell access. If you want to browse in a safer, more secure way, leave Developer mode turned OFF. Note: Switching between Developer and Normal (non-developer) modes will remove user accounts and their associated information from your Chromebook.
On this device, both the recovery button and the dev-switch have been virtualized. Our partners don't really like physical switches - they cost money, take up space on the motherboard, and require holes in the case.
To invoke Recovery mode, you hold down the ESC and Refresh (F3) keys and poke the Power button.
To enter Dev-mode you first invoke Recovery, and at the Recovery screen press Ctrl-D (there's no prompt - you have to know to do it). It will ask you to confirm, then reboot into dev-mode.
Dev-mode works the same as always: It will show the scary boot screen and you need to press Ctrl-D or wait 30 seconds to continue booting.
By default, USB booting is disabled. Once you are in Dev-mode and have a root shell, you can run:
sudo crossystem dev_boot_usb=1
and reboot once to boot from USB drives with Ctrl-U.
Note: Only CrOS formatted images will boot via USB. Other Linux distros will not work.
Sorry, but this device does not support a legacy BIOS mode. It has an ARM cpu, so there is no such mode anyways.
To leave Dev-mode and go back to normal mode, just follow the instructions at the scary boot screen. It will prompt you to confirm.
If you want to leave Dev-mode programmatically, you can run crossystem disable_dev_request=1; reboot from a root shell. There‘s no way to enter Dev-mode programmatically, and just seeing the Recovery screen isn’t enough - you have to use the three-finger salute which hard-resets the machine first. That's to prevent a remote attacker from tricking your machine into dev-mode without your knowledge.
This device uses Das U-Boot to boot the system. You can find the source in the Chromium OS u-boot git tree in the firmware-pit-4482.B branch.
There is also firmware in a custom embedded controller (which handles things like the keyboard), but we won't cover that here as you generally should not need to modify that. You can find the source in the Chromium OS ec git tree (in the pit firmware branch).
If you want some precompiled versions to chain load of nv U-Boot, these should work:
WARNING: Opening the case and fiddling with the stuff inside could easily brick your system and make it unrecoverable. DO NOT ATTEMPT if you are not familiar with this process.
Really. Opening the case will allow you to modify the read-only firmware that makes recovery possible. If someone from “teh internets” says “You need to reflash your BIOS”, they're almost certainly wrong.
Taking apart your laptop is not encouraged. If you have hardware troubles, please seek assistance first from an authorized center. Be advised that disassembly might void warranties or other obligations, so please consult any and all paperwork your received first. If you just want to see what the inside looks like, gaze upon this (click for a high res version):