This page contains information about the Lenovo Thinkpad X131e Chromebook 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.
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.
This device has special requirements for entering recovery mode!
You must first remove all power from the system, both the battery and the AC plug. Then when power is re-applied you have 20 seconds to enter recovery mode with the ESC+Refresh+Power button sequence.
In this system the removal of power sources will force the Embedded Controller to restart and stay in read-only code to ensure the recovery mode is secure.
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.
You'll still have to run "crossystem dev_boot_usb=1" and reboot once to boot from USB drives with Ctrl-U.
Caution: Modifications you make to the system are not supported by Google, may cause hardware issues and may void warranty.
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.