Noobie here... (so treat my input with caution!)
Try following the instructions on this page:
https://github.com/nikolas-n/GNU-Linux- ... Chromebookrelating to archlinuxarm - these are designed to address exactly this problem. Might be easiest to edit it from the terminal shell sudo su from Chrome OS, or from Crouton or a separate (working) arch instance if you have an older one already.
It worked for me from a December 2019 image, but I don't profess to understand systemd or the resolver service enough to know why (but really really wish I did).
I did find it pretty touch-and-go running pacman -Syu though. It messes with the changes and re applying them doesn't seem to always work 100%... The author of the page I cited suggested not updating..
(
So I've only been running pacman -Syu to update the package list, and then manually updating what I need to.
This has now caught up with me, so depending on my last backup's state I may try reinstalling from the March 2020 (current) image.
Input from someone with a better understanding of systemd & the name resolver service would definitely help improve all this...
There are a few other helpful resources out there for the C100 and C201, incl. these:
http://kmkeen.com/c100p-tweaks/2015-11- ... 6-680.html (old, but very useful)
and this one which tweaks the mainline kernel for the C201 (so no touchscreen)
https://github.com/urjaman/arch-c201 (if you goto his linux-c201 folder, he links to a page where he sometimes keeps a copy of his bootable binary package)