Previously (last week) the ArchLinuxARM-armv7-chromebook-latest.tar.gz installer worked for my Samsung XE303C12 Chromebook, but attempts to upgrade the resulting system result in the boot failure using the 5.11.2 kernel as described in this thread.
Today I tried again with an eye towards preventing the kernel upgrade and working with the resulting system. However, there is a new installer with the same name and dated 1 Jul 2021. It may have the newer kernel, as it now produces non-booting SD and USB-based installers for me.
Note to self: keep those old downloads! I found an older installer from 3 Mar 2020 on an old mirror that had not been updated and it works to create a USB installer that boots OK. It's here:
http://mirror.nus.edu.sg/archlinux-arm/os/