Manolo3

Hi, I do not know if this is an Android issue or something else. I just want to know if there is someone here who knows how to change mac adress on a R69 tv-box because my boxes has the same and wrong mac adress. I need to change it permanently to their right mac adress and do not know how or if it is possible? I bought them like this from the net and I can not understand how they can have the same mac adress.