Then remove the write-protect screw, #7 in this photo:
I got that image here:
To enter developer mode press the following key combination:
Esc + Refresh + Power Button
(The refresh button is the 4th button from the left at the top and looks like a curly arrow).
Upon restart, a "scary screen" appears, saying "Chrome OS is missing or damaged".
Press Ctrl+D. From now on you need to press Ctrl+D every time you launch ChromeOS, but soon that won't matter because you'll have Ubuntu instead.
It says "To turn OS verification OFF, press ENTER". Press Enter.
Now it says "OS verification is OFF". After 20 seconds it beeps and says "Your system is transitioning to Developer Mode." After 6 minutes, the "OS Verification is OFF" message appears again, there are three beeps, and the Chromebook restarts.
Now it says "OS verification is OFF". Press Ctrl+D to start ChromeOS.
Press CTRL+ALT+=> (=> is the forward arrow where the F2 key would be on a PC, that is, above the "3" key).
Log in as chronos. No password is needed.
Execute these commands:
This flashes the BIOS to enable SeaBIOS, which allows you to boot from USB.
shell sudo crossystem dev_boot_usb=1 sudo crossystem dev_boot_legacy=1 sudo /usr/share/vboot/bin/set_gbb_flags.sh 0x489
Hold down the power button to turn the Chromebook off.
The prompt says "SeaBIOS" and then "Press ESC for boot menu".
Press the number corresponding to your install USB.
At the "Welcome" box, accept the default selection of "English" and select "install Ubuntu".
At the "Wireless" box, accept the default selection of "I don't want to connect..." and click Continue.
At the "Preparing to install Ubuntu" screen, accept the default selections and click Continue.
When the "Installation type" box appears, click the "Erase disk and install Ubuntu" button. Click "Install Now".
After a minute or so, a box pops up titled "Write the changes to disks?". Click Continue.
In the "Where are you?" box, select your location and click Continue.
In the "Keyboard layout" box, accept the default of "English (US)" and click Continue.
In the "Who are you?" box, enter account information and click Continue.
The installation process was very fast--only 2 or 3 minutes!
When you see a prompt asking you to remove the installation media, do that and press Enter.
When the machine restarts, press Esc and 1. You now have Ubuntu!
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