The `guile-newt' package that is used for the installation UI can't be cross-compiled as it tries to load the `newt' dynamic library when the Guile code is compiled. I've tried to find a solution/fix but I don't know much about how Guile byte-code compilation works.
The compilation error can be reproduced with (#56536 was pushed a few hours ago, so a git pull may be needed): ./pre-inst-env guix build guile-newt --target=aarch64-linux-gnu I think this is one of the last remaining bits before being able to fully cross compile an installation image. — Jean-Pierre De Jesus DIAZ