I also tried with Mac OS X Snow Leopard (which is just one minor version above the one I had installed on the original drive, 10.5 Leopard) by dd'ing the boot disk into my USB drive and it does boot, but after 1 minute or so the apple symbol gets replaced with a prohibited symbol ? and does nothing, even the disk activity LED stops blinking. I have to note that I tried using the createinstallmedia command present in the installer's Resources directory (before my disk died) but I couldn't run it because this mac has a 32 bit OS and the file (according to the file command) is for a x86_64 arch. Creating an HFS+ filesystem and dumping the contents of the dmgs there.dd'ing the images into the USB hard drive (after converting the.I have tried with macOS High Sierra, Yosemite and Mavericks images but they all do the same. My old hard drive died and so I bought a new SSD, I put it in my macbook and plugged in the USB hard drive with the installation media, but no matter what it just won't boot into the installer: I see the bootable disk icon after pressing power + option ⏻ + ⌥, but as soon as I press the ↑ icon I get a prohibited ? icon and nothing more.