https://www.chromium.org/chromium-os/dev...

Above link gives all the gory details about how to reach the write protect disable/enable switch and set it as required for the following steps. You don't have anything to lose except an unsupported chromeos device right?

Reassemble carefully. Since you have it apart this is a good time to upgrade to 8gb memory and a larger SSD if you wish.

See my other guide for details if you are unsure about those hardware upgrades. HP Pavilion Chromebook 14-c050nr RAM & SSD upgrade procedure.