This needs a better error message. # TERM=dumb rcconf Cancelled or /usr/bin/whiptail execution error(256) Like $ TERM=dumb emacs -nw emacs: Terminal type "dumb" is not powerful enough to run Emacs... Please reassign this bug to the correct package. Thanks.
Since whiptail or dialog doesn't print kind messages and rcconf depends on those, rcconf doesn't care TERM problem.