About dual booting, it works just fine using the latest Chromefy script. I think that the original dual boot guide is too much complicated and maybe a little useless now, when it is possible to do it much simpler.
I just downloaded the latest ATB special build (
https://chromium.arnoldthebat.co.uk/special//Camd64OS_R72-11316.B-Special.7z) and unpacked it.
Also downloaded latest Eve recovery (
https://dl.google.com/dl/edgedl/chr....113.1_eve_recovery_stable-channel_mp.bin.zip)
Then I unpacked ATB contents using PeaZip (
http://www.peazip.org/) I only need 2 files: ROOT-A.img and STATE.img.
In Linux, I wrote those 2 files to previously prepared ext4 partitions (I used 8 GB for ROOT, 15 GB for STATE)
(sda5 is my future ROOT-A partition)
(sda8 is my future STATE partition)
Then I run chromefy script. Note that sda5 is my ROOT-A partition, yours can be different
And that's it. I just need to update the location of STATE partition. Open ROOT-A partition (/dev/sda5) and find the /sbin/chromeos_startup and change "STATE_DEV=${ROOTDEV_TYPE}${PARTITION_NUM_STATE}" to "STATE_DEV=${ROOTDEV_TYPE}8" if your STATE partition is /dev/sda8.
Finally update the GRUB.
Now you should be able to load Chrome OS from GRUB.
Note: The state partition although is 15 GB large, it seems like much smaller and can cause running out of free space. So I just opened PartitionManager and resized it 1 MB down and then 1 MB up and it is fixed, it has full size.