(defun reverse-im--translate-char-strict (c)
  "Try to translate C using active translation keymap."
  (let ((to))
    (map-keymap #'(lambda (from value)
                    (when (and (characterp from)
                               (= c from))
                      (setq to (aref value 0))))
                (keymap-parent function-key-map))
    (or to c)))

(defun reverse-im-read-char (orig-fun &rest args)
  "An advice for `read-char' compatible ORIG-FUN called with ARGS."
  (let ((res (apply orig-fun args)))
    (reverse-im--translate-char-strict res)))