Acer C7 Chromebook

Introduction

This page contains information about the Acer C7 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.

Specifications

  • CPU: Intel Sandy Bridge Celeron (might vary on specific model)
  • GPU: Intel Sandy Bridge Mobile
    • 11.6" 1366x768 16:9
    • HDMI port
    • VGA port
  • RAM: 2 GiB or 4GiB DDR3 (might vary on specific model)
  • Disk: 320 GiB HD or 16 GiB SSD (might vary on specific model)
    • USB expansion ports
    • SD slot (SDXC compatible)
  • Networking
    • WiFi 802.11 a/b/g/n
    • Dedicated Ethernet port
    • USB ports can handle Ethernet dongles
  • Power supply: 19V (DC) 2.15A (positive polarity tip)
  • Kensington Security Slot

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.

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.

Introduction

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.

Entering

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.

USB Boot

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.

Legacy Boot

Sorry, but this device does not support a legacy BIOS mode. It predates the launch of that feature and it is not feasible to produce updates of devices in the field.

Leaving

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.

Firmware

This device uses coreboot and Das U-Boot to boot the system. You can find the source in the Chromium OS coreboot git tree and the Chromium OS u-boot git tree in the firmware-parrot-2685.B branches.

What's inside?

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.

Disassembly

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 high res versions):

   

However, we acknowledge that some people like to tinker.  So here's a quick guide to taking it apart.

Access to upgradable/cleanable components

This is very easy to do and gets you access to all the pieces you most likely care about:

  • The hard drive is easy to remove & replace/upgrade
    • 2.5" SATA 2 or SATA 3 drives should work
    • try to get a 7mm tall one (9.5mm will fit, just sans padding)
  • The two memory slots are easy to access
    • The system uses 204-Pin DDR3 SO-DIMM laptop memory
  • The wifi module is easily removable (one screw)
  • The exhaust fan is easily removed (two screws) for cleaning
And here's the details (see image on right for more details):
    • Get a smallish phillips head screw driver -- all screws can be removed with just this
    • Shut the system down and close the lid
    • Flip the laptop over so the bottom is facing up and the warranty seal is closest to you
    • (Step 1) Break the seal that says "warranty is void if seal is broken" -- be aware, you might void your warranty by breaking the seal :)
    • (Step 1) Remove the single screw under the seal
    • (Step 2) Remove the battery
      • (Step 2a) There is a slide near the edge of the battery in the upper right section -- put the tip of the screw driver into the divot and slide it to the right to unlock the battery
      • (Step 2b) While the battery is unlocked, pull it out
    • (Step 3) Place your thumbs on the bottom two feet and pull towards you
      • Alternatively, you can pull on the edge where the battery was
    Check out the high res picture above for overview.

    Access to the rest of the machine

    While it is possible to remove the motherboard entirely, there isn't much of a point. You can see a high res image of what it looks like above if you just want that.

    If you really want to remove it, then here's how:

    • Remove the 18 screws holding it down (does not include the warranty screw)
      • 4 screws: one next to each of the rubber feet
      • 11 screws labeled M2x6 (including one on the cooling fan)
      • 1 screw labeled M2x3 (near the memory module)
      • 1 screw on the the cooling fan (kitty corner to the M2x6 one)
      • 1 screw on the wireless module
      • You do not have to remove other screws (like the ones around the cpu)
    • The top part of the case is now held to the bottom by plastic tabs around the edge
    • Turn the computer onto its side and slowly pry it apart
      • Switch between the sides to slowly work it apart
      • You can press on the center of the motherboard where the empty memory slot is to help

    Firmware Write Protect

    It's a jumper next to the CPU under the black plastic. See the pictures above for more details.

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