Chrome OS devices provide a variety of advanced keyboard and button shortcuts that are useful for debugging. We document those here, as well as highlight some differences between devices with and without keyboards.
See the official support page for non-debug keyboard shortcuts.
Note that some of the below debug keyboard shortcuts are implemented at a very low level and are not keyboard-layout aware. When in doubt, assume debug shortcuts refer to the physical mapping of a US keyboard layout.
Shortcuts with an asterisk (*) also work with tablets/detachables with a keyboard attached.
| Functionality | Shortcut |
|---|---|
| Clean shutdown | Power button, hold for 3 - 8 seconds |
| Hard shutdown | Power button, hold for 8 seconds |
| Screenshot capture | Ctrl + Switch-Window * |
| File feedback / bug report | Alt + Shift + I * |
| Powerwash | Ctrl + Alt + Shift + R from login screen * |
| EC reset | Power + Refresh |
| Recovery mode | See firmware keyboard UI section |
| Developer mode | See firmware keyboard UI section |
| Battery cutoff | Power + Refresh, hold down, remove power for 5 seconds |
| Warm AP reset | Alt + Volume-Up + R |
| Restart Chrome | Alt + Volume-Up + X * |
| Kernel panic/reboot | Alt + Volume-Up + X + X * |
| Reboot EC but don't boot AP | Alt + Volume-Up + Down-Arrow |
| Force EC hibernate | Alt + Volume-Up + H |
| Override USB-C port used for charging | Left-Ctrl + Right-Ctrl + Search + (0 or 1 or 2) * |
| Virtual terminal switching | Ctrl + Alt + F1 (or F2, F3, F4) * |
Notes:
Alt + Volume-Up is treated as the Magic SysRq key. When in Developer mode, you can enable SysRq key combinations as documented in the Linux kernel docs.Recovery mode: Hold Esc + Refresh and press Power.
Recovery mode: Engage the small Reset pinhole with a paperclip, hit Power and continue engaging Reset for 2 seconds. Typically (only?) for chromeboxes with a QWERTY keyboard attached.
Developer mode: To enter Developer Mode, first enter recovery mode, then press Ctrl + D, followed by Enter to accept.
Ctrl + D: Boot the system from the internal disk.Ctrl + U: Boot the system from an external USB stick or SD card. The option crossystem dev_boot_usb=1 must be set from the command line before this option is available.Ctrl + L: Chain-load an alternative bootloader (e.g. SeaBIOS). This may allow booting other Operating Systems more easily. Not all devices are shipped with alternative bootloaders. New alternative bootloaders can be manually installed on the device from Developer Mode. The option crossystem dev_boot_legacy=1 must be set from the command line before this option is available.0 through 9: On newer (2019+) platforms, more than one alternative bootloader can be installed and Ctrl + L will show a selection menu. On these devices, the number keys can be used to directly boot the numbered bootloader without going through the menu.crossystem dev_default_boot=usb can be set to override the default boot behavior if no key combination is pressed for 30 seconds.Some devices do not support Esc + Power + Refresh for entering Recovery Mode:
Power.Ctrl + D on the keyboard, then push the physical recovery button on the Chromebox to accept.Note: An additional, deeper reset (with forced memory retraining) can be triggered on some devices on the way to recovery mode by holding Left-Shift during the normal recovery sequence (i.e., Left-Shift + Esc + Refresh + Power).
Starting in 2018, keyboardless Chrome OS devices are being built, in tablet and detachable form factors. Without a keyboard, some typical keyboard-based debugging shortcuts can't be supported. Below are the shortcuts for performing various system and debugging tasks with only the limited physical buttons and touch screen found on tablets or detachable devices.
Note that some of the following behaviors work on convertible devices when used in tablet mode.
| Functionality | Shortcut |
|---|---|
| Screen off | Power button, short press |
| Clean shutdown | Power button, hold for 3 seconds, select option in menu |
| Hard shutdown | Power button, hold for 10 seconds |
| Screenshot capture | Power + Volume-Down, short press |
| File feedback | Power button, hold for 3 seconds, select option in menu |
| EC reset | Power + Volume-Up, hold for 10 seconds |
| Recovery mode | See firmware menu UI section |
| Developer mode | See firmware menu UI section |
| Battery cutoff | Power + Volume-Up, hold down, remove power for 5 seconds |
| Warm AP reset | See EC debug mode section |
| Restart Chrome | See EC debug mode section |
| Kernel panic/reboot | See EC debug mode section |
Notes:
Help > Report an issue...).The boot firmware screen is accessible through keyboard shortcuts on devices with keyboards; on keyboardless devices, the following methods are supported:
Power + Volume-Up + Volume-Down, hold for 10 seconds. If the screen turns off or on during that period, ignore it and make sure you keep all three buttons held down for the whole 10 second period, then release them.Volume-Up or Volume-Down. This leads to a menu that can be navigated with the volume buttons, and menu items can be selected with the power button.Volume-Up + Volume-Down simultaneously, then select “Confirm Enabling Developer Mode” in the menu.Volume-Down for 3+ seconds, then release: Boot the system from the internal disk.Volume-Up for 3+ seconds, then release: Boot the system from an external USB stick or SD card.Note: An additional, deeper reset (with forced memory retraining) can be triggered on some devices on the way to recovery mode by holding Power + Volume-Up + Volume-Down for 30 seconds (until the LED starts flashing).
Not all debugging shortcuts are implemented with a simple combination of buttons—some are found by utilizing multi-button sequences, initiated after entering a special EC state called “debug mode”. To enter debug mode, press Volume-Up + Volume-Down for 10 seconds. Release once the charging LED starts flashing. Once in debug mode, any of the following actions can be taken, using Volume-Up (U) and Volume-Down (D) buttons.
Supported codes:
| Functionality | Sequence |
|---|---|
| Restart Chrome | UD |
| Kernel panic/crash | UUD |
| Warm reset | DU |
Debug mode is cancelled when a sequence finishes, or after 10 seconds without a volume button press.