The limitation of overclocking is not related to the firmware version. If someone needs a May version, they can download it here, without any queries -
https://yadi.sk/d/949-DCwheW8a7ABesides, it's just a matter of time before one of the more knowledgeable, experienced and long term (not to mention generous and community oriented) members in this forum post details of the mod anyways. If it even works stably - which is just a claim at this point in time. A couple pictures is all that @Hitsxx has to prove it.
Funny fact. The loudest of all about free assistance to the community are those who didn't do anything themselves. Just an observation, nothing personal.