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Toshiba CB30 Chromebook

Introduction

This page contains information about the Toshiba CB30 Chromebook that is interesting and/or useful to software developers. For general information about getting started with developing on ChromiumOS (the open-source version of the software on the Chrome Notebook), see the Chromium OS Developer Guide.

Specifications

Developer Mode

Caution: Modifications you make to the system are not supported by Google, may cause hardware, software or security issues and may void warranty.

Details for working with developer mode can be found on this page.

Running ChromiumOS

Before you start fiddling with your own builds it is strongly recommend to create a recovery USB stick or SD card. As long as you don't disable hardware write protect on the system & EC firmware, you can get your machine back into working order by entering Recovery Mode and plugging in your recovery image. You can create a recovery image from ChromeOS by browsing to [chrome://imageburner](javascript:void(0);) or follow instructions for other OS on the ChromeOS help center site.

You can build and run ChromiumOS on your Toshiba CB30 (versions R32 and later). Follow the quick start guide to setup a build environment. The board name for the Toshiba CB30 is "leon". Build an image and write it to a USB stick or SD card.

To boot your image you will first need to enable booting developer signed images from USB (or SD card). Switch your machine to Developer mode and get to a shell by either via VT2 (Ctrl+Alt+F2) and logging in as root or by logging in as a user (or guest mode), starting a "crosh" shell with Ctrl+Alt+t, and typing "shell". Now run "sudo crossystem dev_boot_usb=1" and reboot "sudo reboot".

Plug your USB stick or SD card in and on the scary "OS Verification is OFF" screen hit Ctrl+u to boot from external media. If all goes well you should see a "ChromiumOS" logo screen. If you want to install your build to the SSD, open a shell and type "sudo /usr/sbin/chromeos-install". Note: This will replace EVERYTHING on your SSD. Use a recovery image if you want to get back to a stock ChromeOS build.

Have fun!

Firmware

This device uses coreboot to boot the system. You can find the source in the ChromiumOS coreboot git tree in the firmware-leon-4389.61.B branches.

Disclaimer

Caution: Modifications you make to your Chromebook's hardware or software are not supported by Google, may compromise your online security, and may void your warranty....now on to the fun stuff.

What's Inside?

Taking apart your Chromebook 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.

The location of the firmware write protection disable screw is indicated by the red arrow below. Remove the screw, and underneath may be a metallic sticker. Remove the sticker (if present) so that the two pads are separated, as in the picture below. Then, boot the system and run "flashrom --wp-disable" to enable writing to the write protected regions of flash.

image