Currently default answer for the question is 'yes', which is not true for install case, but correct for upgrade one.
Changing default answer depending on the mode of the installer looks like a good approach. Idea by Christian (naddy@), implementation and testing are mine. diff /usr/src commit - c5d97e146b0b84b5aaf0732c7ffb8b845cadd04d path + /usr/src blob - c5d0d7f129960a410a8c89af1d480135f6a18d09 file + distrib/miniroot/install.sub --- distrib/miniroot/install.sub +++ distrib/miniroot/install.sub @@ -2042,7 +2042,12 @@ install_disk() { # Install sets from disk. # Ask for the disk device containing the set files. install_disk() { - if ! ask_yn "Is the disk partition already mounted?" yes; then + local _answer + + # In installation mode installer doesn't automount partitions + [[ $MODE == install ]] || _answer=yes + + if ! ask_yn "Is the disk partition already mounted?" $_answer; then ask_which "disk" "contains the $MODE media" \ '$(bsort $(get_dkdevs))' \ '$(get_dkdevs_uninitialized)'