iMac 21.5-inch Mid 2010 won't boot into OS X after installing Ubuntu, will boot into grub rescue So, as the title says, I have an iMac 21.5-inch Mid 2010 model and I installed Windows 8.1 with Boot Camp. After attempting to uninstall Ubuntu and Windows in Disk Utility (in OS X and Recovery) it would always give me an error,
"Partition failed with the error:
The requested size change for the target disk or a related disk is too small. Please try a different disk or partition, or make a larger change."

What I have tried:


I have tried resetting PRAM/NVRAM with Command + Option/Alt + P+R, nothing.
I have tried holding X to Start up from an OS X startup volume when the Mac would otherwise start up from a non-OS X startup volume. Using Startup key combinations for Mac, still nothing (did work before).
I have done things in grub rescue such as ls (lists partitions and disks) and attempted to boot back into Ubuntu.
I have tried holding Option/Alt to get into the startup manager, still boots to grub rescue.
I have tried holding Command + R to boot into Recovery, worked before, not working now.


What I can't do:


Can't use another Mac to do anything such as target disk mode (no firewire cable).


My iMac Specs:

iMac (21.5-inch, Mid 2010) - Technical Specifications

21.5 inch, 3.06 Mhz, has OSX 10.10 installed with Windows and Ubuntu 14.04.2 LTS.
Fixed after many days. I noticed that the keyboard wasn't initializing during boot so I picked up a new keyboard(something I didn't even think of at the time) and it initialized. I held the Option/Alt key and to prevent this from happening again I installed rEFInd.