I learned enough about scheme and guix to boot the install cd like a live cd where you can eject it and keep using it in tmpfs 1. I modify the kernel parameters in grub to change gnu.load to gnu_load so that guix gives a diagnostic guile repl after mounting the cd rather than booting 2. In the repl I go something like: (define dirs (map (lambda (dir) (string-append "/gnu/store/" dir)) (scandir "/real-root/gnu/store"))) To assign a list of all the store objects on the cd to dirs then something like (for-each (lambda (dir) (if (not (access? dir 0)) (symlink (string-append "/real-root" dir) dir))) dirs) to symlink everything in the cd's store into the initrd 3. Then I drop into bash with such like: ,bournish cat /proc/cmdline cd /gnu/store/gnu_loadpathcopiedfromkernelcmdline-system/profile bin/bash export PATH=$(pwd)/sbin:$(pwd)/bin and now I can use all the installed binaries on the cd before the system is booted, in bash. But there are no ptys or anything yet. 4. In bash I remove the install cd overlay and replace it with a tmpfs root: umount /root mount -t tmpfs -osize=$((here I calculate a high fraction of total ram)) none /root cd /real-root ls cp -va bin var tmp home /root # and any other dirs needed but not gnu cp --one-file-system -va /rw-root/upper/. /root/. mount --move /rw-root/upper/dev /root/dev umount /rw-root rm -rf /rw-root mkdir -p /root/gnu/store cd gnu/store find -maxdepth 1 \! -type d; du --maxdepth=1 | sort -n | head 380 # here I make sure glibc is in the output and adjust head 380 if needed. The kernel and modules for example don't need to be copied if ram is tight. cp -van $( {