I only have one suggestion.  Above the input box, there is a list of tags available to help format posts.  Your presentation would benefit from the use of code tags like this:

sudo xzcat devuan_ascii_2.0.0_armhf_chromeacer.img.xz | sudo dd of=REPLACEME bs=2M

This guide should work for all arm64 .img files (including ubuntu, slackware, kali, stickyour .img here....)
all those other arm64 img files you want instead of chromeos. Not just Devuan
and for those that know me as "1 init" or telegram @initVet know i only run Devuan
OR freeBSD.
I will be using Devuan arm64 new release acii 06/06/18.
A little expensive experient. But its useless to me otherwise ))

GUIDE LAWS:
This guide can be distrubted to any one even edited with there os.img file.
simply "Copy Left" applies to this. ( do what ever you want)
I AM NOT RESPONSIBLE IF YOU F**K UP

BEFORE STARTING SPECIAL THANKS TO:
BFCAT ~ (Russia)
ALEXLIKEROCK ~ (Spain)
^ at one stage i was going to give up :$ but these guys rooted me on
think it was the third brick.
(brick = no os boot and no kernel found, no recovery partition)

ALL COMMANDS ARE TO BE PERFORMED ON THE CHROMEBOOK INCLUDING
A.  download file to chromebook
B.  burn img using dd on chromebook
C.  every line must be done on chromebook.

4 TOP TIPS
* IF YOU HAVE A SD SLOT USE THIS EVERYTIME EVEN IF I SAY USB!
*after dropping your chromebook to dev mode (completing of step 1)
read step 3 and compelte the copy of the file part to chromebook (before step3.1)
this way you can copy and paste the commands in blindfolded.
* All commands are inbetwen the pipe lines | | do not copy the pipe
just the content
E.G
    -----
    |pwd |
    -----
    is
    pwd
*read the whole guide to feel yourself doing it.its like a mental thing
helps
* 3 and 4 are from the offical guide so no biggy

OUTLINE
1. drop book to dev mode
2. enable dev firmware update + gnupg
3. downloading img ...
4. burning img... include boot problem
5. recover should somthing go wrong

WHAT YOU NEED
2 SD card or 2 USB sticks 8GB+ each.
Either way this option is already made up for you
if you have a SD SLot you are forced to use this
if you do not have a SD slot you have to use 2 usb sticks.

- windows or mac for step 5 (i use kvm/qume for virtual window)
    + windows 10 is free from microsoft just ignore the product is not activate
- 2 hours tops but take your time it is not a race results are important

WHAT YOU DONT NEED
- DD wrong partion (jump to step 5)
- plug in usb to early(you may end up on a differnet journey)
- if you have followed another guide (jump to step 5)
- distractions (find a quite spot)
- UAC in windows  as this will cause it to fail at 95% write
    + i disabled all windows crap and deleted windows after the burn was tested
        ^ Defender
        ^ firewall
        ^ ran all things in admin
        ^ UAC
    + i had to do several restores
- Using CTRL + C AND CTRL + V IS NOT A GOOD IDEA use the menu three dots to paste.

OPTIONAL TO MAKE LIFE EASY
- create a blank file:
    + copy 3.1 3.2 3.3 3.4 4.2
    + replace links and files to reflect your setup.
    + move this to chromebook g drive is not a bad idea XD 
    + completing this will mean WHEN you get to step 3 you simply start from 3.1.
- install "INSOMINA stay awake" from chrome store to keep the thing from sleeping
    + there should be 3 x Z with a "\" going threw it showing its active. (you need this for step 4)   

COMMON QUESTIONS:
wtf is with the format of this guide?
the devuan insall i use for writting this on does not have a gui so i use nano

what is your setup?
some cheap sd card bought off wish 256gb
some 8gb cheap usb stick bought off ebay came in pack of 5
chrome book r11 (the new one but who cares this guide is generic)
windows on qume/kvm (windows is free for a little while enough to recover your chromebook)

Do you still code for beer?
i am afraid i have stopped drinking so no.

can i add you on telegram?
join a devuan / freebsd group and invite me there i will join.
DO NOT ADD ME TO OTHER OS GROUPS DO NOT MESSAGE ME DIRECTLY UNLESS LINKING
ME TO GROUP.

you cant spell?
i know, do you need a idontcarebear hug to feel better about reading this guide? or is getting
a arm64 install on your device more important?

why did you not take this threw a spellcheck?
i do not have a spell check on my non gui devuan and have things to get on with
use the license agreement and correct it.

why do you start and end with | ?
so some one that is advance can simply cat step |grep "|" to see the commands
------------------------------------------------------------------
1. SET DEV MODE:
WARNING ALL DATA WILL BE LOST AT THIS POINT EVEN IF YOU DO NOT COMPLETE THE TASK
1.1 HOLD esc + refresh and TAP power button (refresh the circle arrow)
1.2 press ctrl + D hit enter
should get a lovely screen saying "os verificatoin is off"
this translates to "you are doing good move to next step"
then it will say your chrome book is transitioning (maybe removing spyware i dont know)
it even has a spinning circle to show how well you are doing only if it was a blinky star.
go make a brew as we say in England (tea)
1.3 press ctrl + D  to boot into chrome
1.4 log into chromebook.

-----------------------------------------------------------------
STEP 2: DEV FIRMWARE
2.1 ctrl + alt + T for terminal
2.2 should log you in as chronos
2.3 starting with a easy command get to shell
    ------
    |shell|
    ------
    ------
2.4    |sudo bash|
    ------
should move you to localhost chronos

    ----
2.5    |chromeos-firmwareupdate --mode=todev|
    ----
now it boots from usb!
NOW BEFORE MOVING TO 2.6 PLEASE MAKE SURE IT SAYS
    "INSERT BOOTABLE MEDIA INTO USB / SDCARD SLOT AND PRESS CTRL+U in developer" or somthing like this

NOTE DO NOT END UP LIKE ME READ!
now it is important you do not get excited here and boot off a pre burned usb disk like i did
and end up jumping to step5 (you only fail when you give up so it took 5 lessons for me)
if you do this you will whipe the chromeos (you want this) but it will not install your image properly as it
is either DD on the wrong device or some random iso you download
either way keep step 5 to hand if you do become creative please let us know XD

2.6  type "exit and hit return do this 3 times till the window closes.
    ------
    |exit|
    ------
hit return
2.6 x3 till window closes

reboot

2.7  ctrl + D to boot developer (i really dont know why we press ctrl+D) "os verification message"
2.8 login
If you short of time stop and continue another time... here you can break
2.9 repeat 2,1, 2.2, 2.3 and 2.4
2.9.1 i cant get GnuPG on my chromebook to work so i skipped verify step. But included should you manage to get it work
so i skipped 3.4
2.9.2 now we are ready for step 3
------------------------------------------------------------------
STEP 3: DOWNLOADING
    MAKE A COPY OF THIS STEP 3 AND 4!!!!
    now rename the copy as "formyarm" or somthing.
    DEVUAN USERS: just replace 3.2.
    OTHERS: REPLEACE ALL URLS IN 3.1, 3.2 3.3 AND 3.4 WITH YOUR OS URL
    MOVE THIS COPY TO YOUR CHROMEBOOK use gmail or telegram or somthing.
    on the chromebook i stuck all my install files in /home/chronos/tempfolder/
3.1 uv'course i made the folder "tempfolder"
        ------
        |cd /home/chronos|
        ------       
        |mkdir tempfolder|
        ------       
        |cd tempfolder|
        ------
3.2 go to the following link using chrome book:
https://mirror.leaseweb.com/devuan/devu … /embedded/

3.3 locate your device and dl the img file using curl using the window setup in step 2.9.1
    -----
    |curl -O https://mirror.leaseweb.com/devuan/devu … er.img.xz|
    -----
3.4 download sums and signature:
    -----
    |curl -O https://files.devuan.org/devuan_ascii/e … HA256SUMS|
    ----
    |curl -O https://files.devuan.org/devuan_ascii/e … 6SUMS.asc|
    -----
3.5 Verify: ( i cant gpg to work so i skipped this)
    -----
    |gpg --verify SHA256SUMS.asc && sha256sum -c SHA256SUMS|
    -----
------------------------------------------------------------------
4. IMAGE
This part is very important so pay extra attention to this. This could go two ways
YOU REBUILDING THE CHROME BOOK TO START FROM STEP 1 AGAIN (step 5 then step 1 -4)
OR
YOU BURNING THE IMAGE CORRECTLY READY TO BOOT.
lets start by doing things properly:
    ------   
4.1     |df -aTh|
    -----
now plug in your usb/SD card

run     -----
    |df -aTh|
    ----
Do you see your disk?
    if yes move to 4.2 if no move to 4.1.1
if the list is to long use "ctrl" + "-" symbol zooms out  (I cant find "page up")
you should be able to see the added storage plus the space.
note this down and edit the line in 4.2 with this replacing the "REPLACEME" with it stated
so if it is /dev/sda1
use /dev/sda1

4.1.1
WARNING MESS THIS UP YOU WILL LOSE YOUR MAIN MACHINE TO.
Plug this into your main machine (It should be a devuan install if not I forgive you
but i cant help you)
install gparted using
    -----   
    |apt-get install gparted|
    -----
launch gparted select the usb device on the top right first
then clear what ever is  on it
make a table : msdos
format to: ext4
(default who cares it just needs to be seen)
BEFORE PRESSING THE TICK!!! MAKE SURE IT IS STILL THE USB STICK
go back to step 4.1 when finished, if it fails second time find another usb
i orginally tried it with a fancy san orbit 32gb ring thing....

4.2 enable insomina stay awake.

IMPORTANT NOTICE: EVERYTHING WILL BE SLOW!!  in 4.3

4.3 now comes the burn IF YOU HAVE A SDSLOT USE THIS.
from step 4.1 you got the mount point of your usb so just remove REPLACEME and stick it there as is
somthing like "/dev/sda1" by purpoes i did not include a example encase you image
the wrong partition
NOTE:
do not add extra charcters like / example: /dev/sda1/ or some werid thing just as is, you want the whole disk
not the content so no extra "/" just /dev/sda1
    -----
    |sudo xzcat devuan_ascii_2.0.0_armhf_chromeacer.img.xz | sudo dd of=REPLACEME bs=2M|
    -----

this takes about 1 hour + a bit (maybe just me as i got crap storage off ebay) i continued to setup my next
project while i waited. total time 3860.39 seconds

once complete DO NOT REMOVE THE USB STICK! it will tell you its complete its self
simply type reboot do not unplug or any weird thing
    -----
    |reboot|
    -----
4.5 press ctrl + U when it says "verification is off"
if it beeps we have more work to do woo hoo so close )) follow 4.6.1

4.6.1 do 2.1, 2.2, 2.3, 2.4 and 2.5 again and reboot and try again
4.6.2 try DD disk dump to sd card
4.6.3 use chromeman usb boot tool.https://mrchromebox.tech/

------------------------------------------------------------------------
STEP 5:
BEFORE READING THE GOOGLE LINK
5.1 If you have a sd slot use this USB will not work. USB crew with no SD slot you can use USB
5.2 visit this url and go down to the bit "install the chrome app on your window or apple"
    - https://support.google.com/chromebook/answer/1080595
    - i used kvm qume and mounted my usb that way to a virtual instance of windows. found a use for windows
    - windows free just ignore the activation window
5.3 while its burning the image get back to chromebook hit space bar and get yourself to "verify os on" again
5.4 boot your chrome book with your media disconnected (SD CARD/ USB).
5.6 when it says "chrome os not found" i forgot the rest of the message this is the point to plug your media.
5.7 once it has finished setup the chrome book as though you are a normal user so it can download the rest of
the spyware it needs to function.
5.8 you can now start from step 1.

------------------------------------------------------------------------
MY LOLS WORTH LAUGHING AT
1. I Gparted my root partition )) on my main machine XD was not paying attention (Thank you for the reinstall while
i was at work you know who you are) lucky i do not store my vms on same hard disks
2 I tried installing full flavor devuan
    2.1 lols no support for 1366 x768 even after running xandr
    2.2 it fails after loading the kernel module got around this but was left with 2.1.
3. I tried curl Gnupg
4. I bricked the device with no kernel no recovery boot x 5 times
5. I tried recoverying with a usb stick (must use sd slot) as usb is disabled
6. I wrote the image from my desktop and tried booting up from it and could not see why it kept failing
7. i also whiped my usb that had a lot of my code on it :$ got a backup (was trying different usbs,
fustrated wonder why it dont boot from USB, when i had usb boot disabled/wrong format/or not burned on chromebook)
a lot more lols but those are the main ones

what did i accomplish... well a device that i can carry with me that i am not ashamed of!