MacOS – Yosemite Grey Screen with 3d Party SSD not a trim issue

The simple answer is it sounds like your operating system is totally fried. You will need to do a full erase (zero out all data and not the quick erase drive option) of your hard drive. Reinstall a legal copy of Mac OS X. This is absolutely key. It's just plain out not smart to install anything illegal. It is so easy to add key logging or any other type of malicious software into illegal copies of operating systems. Furthermore, they could easily install stuff that could grab personal data such as passwords, bank account information, or use your computer as a zombie to hide illegal activity. You could get easily screwed. Do you want that? I don't think so. Who would? Just buck up the cost and get a legal copy of OS X. It's worth every dollar and the peace of mind.

If you can't afford Mac OS X install a stable build of Linux, but I scratch my head as to why would someone have a Mac but not run Mac OS X as their primary OS. Doesn't make sense. You might as well have a PC.

Solved: Booted to Single-User mode and disabled Radeon GPU.

Details of investigation:

Initially I suspected hard-drive corruption and went about trying to remedy that. Unsuccessfully, I tried the following, with each continuing to hang as described above:

• Safe boot
• Boot into recovery (including Internet Recovery)
• Boot from install media on USB drive
• Boot from OS X installation on USB drive
• Clear NVRAM
• Reset SMC

I also ran the Apple Hardware Test many times without it finding any issues.

Verbose safe boot (Cmd+Shift+V) output everything that I'd expect to see but would then hang as described above.

After coming across more posts online of GPU related problems I revisited this as the cause:

• https://discussions.apple.com/message/22751155#22751155
• https://discussions.apple.com/thread/4766577?start=210&tstart=0

Attempting to boot Ubuntu from a USB flash drive, I could only get as far as Grub. When trying to boot Ubuntu Desktop or run the graphicstest in Grub the system would hang.

At this point, running Apple Hardware Test hung right before the end of the standard test, possibly [guessing] when doing a video test.

Based on the advice in the Apple Discussions posts above I did the following:

• Boot into Single-User mode
• Execute the following commands:

    /sbin/fsck -fy /
    /sbin/mount -uw /
    mkdir /Disabled_System_Library_Extensions
    cd /Disabled_System_Library_Extensions
    mv /System/Library/Extensions/ATI* .
    mv /System/Library/Extensions/AMD* .
    touch /System/Library/Extensions
    exit

This time the machine booted all the way through. However, graphics are extremely slow, even just transitions when minimizing windows. I will be taking my MBP to Apple to demand a replacement as the large number of reports of others facing similar issues makes it look like a recurrence of a similar GPU-related failure that resulted in them doing a recall.