I try to boot osx from usb which has been made as boot disk due to my mac mini file system choas. I press the button 'c'/'option' after mac running, but both cases do not trigger the menu that let me to choose boot from usb.
After the light on usb blinks 100~200 times, it stop. Then it continue to enter the procedure that recovery the file system then fail and auto shutdown.
Does anyone met the same problem? I am not sure if usb has problem or my mac's problem?