  We study the functional identity $G(x)f(x)=H(x)$ on a division ring $D$,
where $f \colon D\to D$ is an additive map and $G(X)\ne 0, H(X)$ are
generalized polynomials in the variable $X$ with coefficients in $D$.
Precisely, it is proved that either $D$ is finite-dimensional over its center
or $f$ is an elementary operator. Applying the result and its consequences, we
prove that if $D$ is a noncommutative division ring of characteristic not $2$,
then the only solution of additive maps $f, g$ on $D$ satisfying the identity
$f(x) = x^n g(x^{-1})$ with $n\ne 2$ a positive integer is the trivial case,
that is, $f=0$ and $g=0$. This extends Catalano and Merch\'{a}n's result in
2023 to get a complete solution.
