Actually it didnt reuse the footage from Robot Jox in any way, form or shape. The robot was of completely different design. As for the connection, theres the Crash and Burn subtitle and even the use of some musical cues from the RJ. And also, t was officially released in some countries as RJ 2 and the Polish VHS cover is seen here.

True, the plot doesn't have anything to do with its prequel, and it has that "The Thing" feel to it when a group of people is trapped inside the tv station, knowing that one of them is Unicom's cyborg, but not knowing who, but in some countries its officially the sequel ever since its release and was also produced by Charles Band who produced RJ right after RJ. Many sequels have little or nothing to do with their original movies, take CHUD 2 for example, yet its still CHUD 2

This actually isn't connected in any way to Robot Jox, other than that this film reused footage from the film and that "Crash and Burn" was a notable quote said in Robot Jox.