Have a mid 2010 macbook pro and when loading a normal usb stick to install an osx like yosemite, mavericks, high sierra it loads a little progress bar goes up about half ways of half and just stops the activity light of flash drive is doing nothing. I tried another motherboard, the motherboards by the way are used pulled working according to ebay seller he even sent me another motherboard i got today and tried but same exact issue. I also redone the usb sticks different osx's, another hdd, pram reset function, but same issue. Anyone know what could be? I haven't tried another ram stick yet because i didn't know i had another laying around but i just found a 2gb stick i can try the one i been trying with is a 2gb stick too.