yeah, my theory is that this robot:
becomes this maverick and the original source of the maverick virus.
allow me to explain, as you may know Zero is generally referred to as patient zero of the maverick virus a transmittable virus that more or less is rabies to androids.
however the thing is Zero was based on Bass who was based on the modified Rock(the original Megaman) but heres the funny thing... Bass went maverick.
this means that something Dr. Light did caused the maverick virus, and heres the proof it was done to Rock in the original upgrade to combat the robots that Wily had reprogrammed.
in megaman 7 right at the end after Dr.Wily surrenders Rock arms his buster and aims it as his head and starts charging it.
until this point it was generally known that Rock was a robot and bound by asimov's laws, which dr. Wily claims in"you forget, Megaman. robots cannot harm humans" to which Megaman responds "I am more then a robot!! die wily!!", had the self destruct of Wily's base and treble and bass saving wily not stopped him Megaman would of murdered him in cold blood.
now what could of caused Rock to be able to break Asimov's laws? how about a program introduced to allow him to adapt to his mission and combat in real-time? see Rock wasn't originally made for combat, he was a robot made to assist Dr.Light in the lab/house.
but to make him able to stand a chance in combat with robots made for hard labor and actual warfare Light would need to supe him up.
and he did by adding a program that could copy and adapt to the attacks and powers of his enemies, this is how he gains new abilities with each victory.
Dr. Light had inadvertently made Rock the singularity, a learning and self-improving machine.
but heres the thing, what would that program do if by logical reasoning Rock had to fight a human? it would adapt, allowing Rock to override asimov's laws when he saw fit.
that program eventually evolved into the maverick virus inside of Zero, cause remember Zero was a 3rd generation clone of the modified Rock.
now to the other part of this theory: how is Rock=Vile?
Vile is not only immune to both the maverick virus(the one that came from Zero) but also the Sigma virus(the off-shoot born of Sigma's infection) but hes able to turn it on and off at will, the only androids immune to the virus are those already infected... and X.
Vile was also a long standing maverick hunter before Sigma's declaration of war on humanity, during this time he was always seen as a loose cannon and was one of the veteran hunters.
the fact that he is able to at will turn make the virus inert is beyond strange, no other android other then Vile and X had this level of immunity, not even Zero and Sigma who both later succumbed to their own strains.
this shows that on fundamental level of programming, X and Vile are the same.
this could all be coincidence or it could be real.
seeing as it'll be a long time til we see another Megaman game, let alone one set in the original universe, we could never know.