As noted, take it apart and remove a screw. I think some newer ones can be switched to developer mode in other ways. Then install seabios or the like and then

As noted, take it apart and remove a screw. I think some newer ones can be switched to developer mode in other ways. Then install seabios or the like and then neverware cloudready (or whatever its named now) to get a generic but supported chromeos. The arm chromebooks are pretty sad for support, the x86 ones are the way to go.