Hi!
Just would like to share some my experience on this after spending half of weekend with different tests how to build Thin Client based on Raspberry Pi 3:
So far I was able to successfully use only this image:
Raspberry Pi Thin Client project
Bundled Horizon Client 4.x worked absolutely fine during my tests in Blast mode.
But the ideal scenario of course to have original Horizon Client for Linux on ARM (aarch64).
Thank you!