I had trouble with repo-install sources being cached in $HOME/.fasls as it uses *load-truename* and would try to find repos in the wrong directory.

The quick fix was to

(setf repo-install::*installer-directory*
      #P"/home/billitch/dev/lisp/")

after booting repo-install in $HOME/.sbclrc . Now it looks like this :

(load "/home/billitch/dev/lisp/repo-install/boot.lisp")
(setf repo-install::*installer-directory*
      #P"/home/billitch/dev/lisp/")
(repo-install:add-detected-repos)