Not booting , even from USB
Dear forum
I have a rare (for me ) problem with a macbook pro 13 inch 2012 , the model of the motherboard is 820-3115b . It gives green and orange light on the charger , it starts normally with the dong and comes to the flashing question mark foleder and then nothing ...
Most of you will say its the harddisk cable , exactly my thought as well but after changing 5 cables still same thing ... and it does not boot from usb either , tried asd , external boot disk and cd .... nothing .
It does read from the usb as I can see the light flashing on my usb and external disk but still the irritating flashing folder....
Any ideas anyone ?
I did try disconecting everything one by one , the cd , the battery and so on , tried to change the ram several times ..... no change
I f anyone had this problem please advice :)
thank you in advance for your time .
Ist dies eine gute Frage?
3 
1 
Has the drive ever worked internally?
von mayer
Yes it has :) That doesnt answer the question why the usb boot doesnt work though , even if the drive isnt working (changed it 3 times) the mbp should be able to boot to ASD or usb but it just refuses....
von Nacora