[Libguestfs] virt-builder: --ssh-inject fails because it is executed before --firstboot-command?

Version 1.34.6 (on Debian Stretch) Using virt-builder I tried to create a user and inject my ssh key: virt-builder -v -x centos-7.4 --output testimage --format qcow2 --selinux-relabel --hostname testimage --firstboot-command 'useradd -m -p "" dummy' --firstboot-command 'chage -d 0 dummy' --ssh-inject dummy ... [ 16.1] Installing firstboot command: useradd -m -p "" dummy [ 16.1] Installing firstboot command: chage -d 0 dummy [ 16.1] SSH key inject: dummy virt-builder: error: ssh-inject: the user dummy does not exist on the guest (Full debug output attached) Seems like this can never work as the injection is carried out before the first boot. Is this a bug in my version? Or is this limited to users that are already in the image? Guido