My Mac Mini install has fallen, and it can't get up??

First, I like to commend the PinGUY OS guys on making a pretty awesome distribution. Hopefully, I will able to donate a little to keep the project alive and maintained!

I installed PinGUY OS on my Mac Mini. This is the partition table (sizes are just best guess)

efi boot partition: about 200MB
OSX Volume (Mac OS X Extended) 794GB
Linux Volume (ext4) about 170GB
Linux Swap (Linux Swap)

My first install, I put PinGuy OS the third volume. Then put an MBR with Grub on the same volume. Both OS X and PinGuy booted fine. I would just need to hold down the ALT key on boot, and it would bring to the OS X screen letting me choose to boot from OS X; OS X 10.10 Recovery Disk; Or "Windows". Windows as it was labeled by OS X, but was really the Linux boot partition.

If I selected "Windows" it would boot from the Linux volume, and I'd get a GRUB menu, then boot into PinGuy OS.

Well... all of a sudden it broke last night... When I select the option for PinGuy OS, I get a black screen with a flashing cursor. Obviously, for some reason, EFI is not finding a bootable volume anymore.

Right before this happened, changed the partition size of the Linux Ext4 and Linux Swap partition. During install, I had accidentally installed Linux on my swap partition and vice-versa.

BUT after it booted just fine to both OS X and Linux. This morning I logged out of Linux to reboot into OS X. Then when I tried going back into Linux, I got the black screen. Tried reinstalling, still nothing...

I read a pretty much the answer I need from a few posts down. But I have another question: if I boot to grub from the main MBR, can it still load OS X from Grub???

Also, wil Grub over-write the 200MB EFI partition to its own???

In the meantime, I plan to start reading up on UEFI, as I'm not too familiar with it. Other than UEFI can load drivers and access a lot more memory than a standard BIOS.

Thanks for any pointers! :-)