- 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
- Switching between Developer and Normal (non-developer) modes will remove user accounts and their associated information from your Chromebook
Entering Developer Mode
On Pixel, both the recovery button and the dev-switch have been virtualized.
To invoke Recovery mode, you hold down the ESC and Refresh (F3) keys and press the Power button for at least 200ms (until the keyboard backlight comes on). If you don’t hold it for long enough, then it won’t work.
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=1and reboot once to boot from USB drives with Ctrl-U.
Legacy Boot
This device includes an older version of SeaBIOS firmware which supports booting images directly like a legacy BIOS would.
- The Pixel’s BIOS does not provide a GUI interface
- You will need to manually boot/install your alternative system.
- Like USB boot, support for this is disabled by default.
You need to get into Dev-mode first and then run:
sudo crossystem dev_boot_legacy=1and reboot once to boot legacy images with Ctrl-L.
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 key combination which hard-resets the machine first. That’s to prevent a remote attacker from tricking your machine into dev-mode without your knowledge.