Ex-link cable question

[juusso]

Can it be used on the newer firmwares to change the current firmware version number to revert to an older firmware?

No, the console is restricted by samsung and only limited input is enabled. So you can`t enter any useful command.
ExLink helps if you need format /mtd_rwarea to reset hotel mode hack. Here are some other useful functions too, but i`m sure - you do not need it