How Can I Make An OS X Mountain Lion USB Or SD Installer?
We recommend downloading Lion Disk Maker. It's an app that lets you make a bootable installer for OS X 10.6, 10.7 or 10.8. Once you have the app, download the disk image for OS X Mountain Lion from the Mac App Store. Launch Lion Disk Maker and choose 10.8. Find and select the OS X Mountain Lion disk image, then mount your USB drive, SD card, or DVD. Select the partition and start the process.