Reverse a hexadecimal number in bash

Is there a simple command to reverse an hexadecimal number? For example, given the hexadecimal number: 030201 The output should be: 010203 Using the rev command, I get the following: 102030 **Update** $ bash --version | head -n1 GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu) $ xxd -version xxd V1.10 27oct98 by Juergen Weigert $ rev --version rev from util-linux 2.20.1