I had previously rooted my Nexus 7 and installed CyanogenMod, but I wanted to bring it back to stock. I flashed the stock firmware back onto it using Nexus Root Toolkit and I OEM Locked the bootloader, and now when I turn it on, it hangs at the Google screen. It's as if Android is missing completely. I cannot unlock the bootloader as well, as it freezes when I select yes to unlock bootloader. Can anyone help me get Android back?