Thinkpad X13s running ARM64 Ubuntu
Basically I uncompressed a previously installed Ubuntu system, via USB and took the prebuilt Linux and EFI loader from the archiso project to make it work with mine.
From r/ #thinkpad
Src: https://www.reddit.com/r/thinkpad/comments/y9t4ns/thinkpad_x13s_running_arm64_ubuntu/
UPD: Added one more image