Thank you Thomas for the post-mortem. > In the end, I reinstallled Guix from scratch […] I couldn't get the > chroot approach to work properly (maybe with more time, ...).
Though there is little difference betweem reconfigure and reinstall if the chroot is set up properly, I should better have adviced to avoid the trouble and reinstall. Imitating a booted system with chroot has too individual requirements. Anyway. Good your system is working again now. :) Regards, Florian