ChromeOS

• Medion Chromebook S2015

1. Hold [ESC] and [Refresh] buttons and press [Power] button
2. ignore messages and press Ctrl+D
3. confirm with [Enter]
4. press Ctrl+D again (or wait)
5. reboot takes ~30s
6. you're now a developer.

There could be provisioning information still left on the device. Log in with an arbitrary Google account, update the system and go to chrome://policy. Load the policies, wait a bit, shut down and try again.

1. Boot
2. Ctrl+Alt+T for Terminal.
3. sudo su
4. crossystem dev_boot_usb=1 dev_boot_signed_only=0
5. reboot
6. hit Ctrl+U

• MrChromebox – Custom coreboot firmware and firmware utilities for your Chromebook/Chromebox