Difference between revisions of "FAQ/Reverting to ChromeOS"

Latest revision as of 18:34, 17 July 2017

Back to ChromeOS

At some point, you may wish to return your Chromebook to its original factory state. This is a fairly simple operation as long as you read, understand, and follow the procedure below.

Restore the stock firmware

If you flashed your ChromeOS device's firmware to install GalliumOS, you may have to restore the stock firmware before resetting ChromeOS.

NOTE: if you used chrx to install GalliumOS, or only updated your device's RW_LEGACY firmware, then skip ahead to the next section as your device is still running the stock/factory firmware.

Regardless if you flashed your device with BOOT_STUB firmware, or a Legacy boot or UEFI Full ROM firmware, the easiest way to restore the stock firmware is with MrChromebox's ChromeOS Firmware Utility Script. Open a terminal window, then copy the URL to download/run the Firmware Utility Script and paste into the terminal window, then hit enter:

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

On the main menu of the ChromeOS Firmware Utility Script, options will be available to restore either the stock BOOT_STUB firmware or the full stock firmware, depending on your device and type of firmware it is currently running. Select the option available for your device and follow the script's prompts/instructions. If you're restoring the full stock firmware, you will be prompted to supply your stock firmware backup on USB; if you don't have one, the script will supply a backup for you.

Once the stock firmware has been restored, chose the 'poweroff' (p) option from the script to shut down your ChromeOS device.

Use ChromeOS Recovery Media

Recovery Mode is a built-in boot mode of the stock ChromeOS firmware which allows for your ChromeOS device to be quickly and easily reset to factory-fresh state. You will need to create Recovery Media from another device using Google's ChromeOS Recovery Tool. The instructions for doing so can be found here.

Once the recovery media has been prepared, you need to boot your ChromeOS device into Recovery Mode. On Chromebooks, this is done by pressing ESC + Refresh + Power simultaneously. On Chromeboxes, normally there is a recovery button when must be depressed via paperclip (eg) at power on.

When booted into Recovery Mode, you will see a screen with an exclamation point and the text 'ChromeOS is missing or damaged.' At this point, simply insert the recovery media and your device will begin the recovery process. All data on the internal storage will be wiped, the normal ChromeOS partition layout will be restored, and any updated RW_LEGACY firmware will be reset.

NOTE: If you set the firmware boot flags (GBB Flags) using MrChromebox's Firmware Utility Script, those are *not* reset by the recovery process, and will need to be reset separately afterwards.

Resetting the Firmware Boot Flags (GBB Flags)

If you removed the firmware write-protect screw and set the Firmware boot flags / GBB flags (using MrChromebox's script or otherwise), they will likely need to be reset. This is easily done from a ChromeOS shell, but if your flags are set to boot in Legacy Boot mode by default, you may need to use CTRL+D to boot ChromeOS.

Once ChromeOS is booted to the login screen, open up a terminal via CTRL+ALT+F2 (forward arrow --> on a ChromeOS keyboard), then login as 'chronos'; no password is required. To reset the Firmware boot flags, simply type the command below, then press enter:

sudo /usr/share/vboot/bin/set_gbb_flags.sh 0x0

then reboot: sudo reboot

Exiting Developer Mode

Upon boot, simply press the space bar on the Developer Mode splash screen (OS Verification is Off). You will be prompted to confirm, and upon doing so the system will revert back to standard / verified boot mode, completing your transition back to stock. If pressing the space bar produces an angry beep, it means that your Firmware Boot flags are set to prevent exiting Developer Mode, and must be reset per the instructions above.