Flashing FW on CrOS

Requirements link

• A Chromebook
• A USB drive larger than 8 gigabytes
• Internet connection
• Yo brain

Step 1: Enabling Developer Mode link

1. Press the esc + refresh + power buttons all at once on your Chromebook. Doing so will bring you to a screen that will prompt you to insert a USB stick or SD card.
2. On that screen, press ctrl + d. It will prompt you if you want to turn off OS verification. Press ENTER. Your Chromebook will restart and present a screen that says OS verification is OFF.
3. ChromeOS will then display a message for 30 seconds about transitioning the system to developer mode.
4. Once done, the Chromebook will restart into developer mode. Now, you can flash custom firmware.

Step 2: Disabling Write Protection: link

1. Open up the back of your Chromebook. There are screws under all 4 rubber feet.
2. Find the cable going from the battery to the motherbord
3. Pull back the metal cover protecting the cable.
4. Gently lift up the cable.
5. Plug in your charger, then boot chromeOS with the battery unplugged.
6. Flash FW (see below)

Step 3: Firmware link

To keep it breif, UEFI firmware allows the Chromebook to become any other laptop. This means you will lose access to chromeOS. RW_Legacy allows you to dualboot chromeOS along with Linux.

1. Open a terminal via VT-2 by pressing ctrl + alt + →.
2. Log in as user chronos. Note that there should be no password unless you set one yourself.
3. Run the Firmware Utility Script:

  cd; curl -LO mrchromebox.tech/firmware-util.sh && sudo bash firmware-util.sh
  

If you encounter certificate related errors when downloading the script from ChromeOS, then add -k to the curl command and script command to bypass SSL certificate checking as so:

  cd; curl -LOk mrchromebox.tech/firmware-util.sh && sudo bash firmware-util.sh
  

4. Select the firmware you would like to flash.
5. Follow the on-screen prompts. Once you are done, you should reboot into the new firmware! Keep in mind that the first boot will always take longer due to a process called “memory training”. DO NOT power off the device at any time during the first boot.