The original ‘SeaBios’ BIOS on my Acer c720p was a little clunky, so I decided to make the plunge and update it to a ‘proper’ Linux-friendly BIOS..    There is a known/good one available, but it is UEFI-only, so will involve changing the filesystem/partition layout on an existing system..

Disk /dev/sda: 119.2 GiB, 128035676160 bytes, 250069680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 245453FD-909E-4796-8A0E-1ABD9BB499DB
Device    Start  End       Sectors   Size   Type
/dev/sda1 2048   309247    307200    150M   EFI System
/dev/sda2 309248 250066943 249757696 119.1G Linux filesystem

More details are here:    https://www.reddit.com/r/chrultrabook/comments/4t8kd5/flashing_script_for_uefi_available

To be on the safe side, I downloaded the top-level install script onto a usb ‘recovery’ stick beforehand, and made sure that network support was enabled..  The direct link to the script is at:  https://coolstar.org/chromebook/setup-firmware.sh

As usual, this is not for the faint-of-heart, as you can brick your system!     The script does include the option to backup the ‘old’ bios, and this is always recommended..     It recognised my system and model correctly, and everything went smoothly..     I decided to just do a clean (re)install of the KDE Spin of Fedora 26 from a USB stick, and this also went OK..

# uname -a
Linux rg720 4.13.0-rc4 #1 SMP Thu Aug 10 17:45:38 PDT 2017 x86_64 x86_64 x86_64 GNU/Linux

Robert Gadsdon.   August 11, 2017.