Grub on Mac via EFI (Linux: /dev/sda1 Darwin: /dev/disk0s1) (MacBook Pro Early 2011 if it matters)

Presumably Windows messed up with your OS X boot code. You have to rebuild this code. Since OS X tools can not handle a false flagged partition you have to set the correct partition flag and afterwards rebuild the boot code using OS X Disk Utility.

Since you can't boot from the now unaccessible recovery partition you have to have Linux-tools and a second Mac (accessing your messed up hard disk via target mode 2nd stage) or a OS X install DVD/USB-key by the hand.

Let's go:

Download the latest gParted iso file here: gParted

Burn the iso to a CD or transfer it using the tool of your choice to a USB drive. For help to create a gParted Live-USB look here: Live-USB

Boot your Mac using gParted-Linux.

Go to the gParted-tool. (First window will be opened automagically on the desk.) Select the (probably your first) HFS+ partition and do the right click. Be aware, this is not the first 200 MB EFI-partition!!!

Now edit the partition info.

• Tick the square for the msft-type.

• Remove the mark. Do not mark any of the available marks.

• Write out the changes.

Leave the tool and reboot into a OS X-Install-DVD or prepared OS X install-USB-key (or as forementioned connect your dead Mac-HDD to the other Mac via Firewire or TB now accessing the disk in target mode)

Open OS X Disk Utility.

• Tick on the Apple HDD, let Disk Utility repair the partition layout.

• Check the OS X-partition too and reboot into your OS X again.

Hold the alt-key and choose the OS X boot volume. Be happy.

for background stuff from the sources please check search for:

1. Apple tech notes
2. steelpangolin

or search for "apple tech notes tn2166" or "steelpangolin invalid-bs_jmpboot-in-boot-block-000000/"

Update:

1. this is for hdd that has NO hybrid partition only, sorry otherwise this is not for you
2. please be prepared prior to any further coming desaster

so

• make a bootable copy of the stock or newly installed OSX (minimum space required ca. 10GB) to an external drive

or

• create a bootable setup-stick of the setup-image (contained in any OSX Install.app) This will speed up the recovery and makes you more independent from huge downloads esp. over slow lines.

Note: El Capitan (OS X 10.11) prevents users from selecting rEFInd and common Linux distributions from the Startup Disk pane. The new preferred method is to install rEFInd into the an EFI partition. My answer, to an unrelated question, outlines this new preferred method to start the rEFInd Boot Manager and Linux operating systems. The answer, given below, applies to Yosemite (OS X 10.10) and possibly earlier versions of OS X.

Personally, I installed rEFInd on my computer to its own partition. This prevents the problems you are encountering. Everything ./install.sh installed went to this partition. If I want to remove rEFInd, I can simply erase or remove the partition. Of course both are unnecessary, because I can turn rEFInd on and off at will. I just go to the Startup window in System Preferences select my boot partition. This computer has OS X, Windows, Fedora and rEFInd installed.

I also can select the boot partition under Windows by using BootCamp and by holding the Option key down at startup. The command diskutil list produces:

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Marlin                  300.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data Coelacanth              98.9 GB    disk0s4
   5:                  Apple_HFS Linux HFS+ ESP          209.7 MB   disk0s5
   6: 0FC63DAF-8483-4772-8E79-3D69D8477DE4               524.3 MB   disk0s6
   7:                  Linux LVM                         98.6 GB    disk0s7
   8:                  Apple_HFS rEFInd                  939.5 MB   disk0s8

Note, the rEFInd partition is ~ 1 GB in size. In fact, it can be as small as 100 MB. When I setup this computer, I used the Disk Utility application to create the rEFInd partition. If I would have used the gpt command, I could have created a smaller partition. Neither OS X, Windows, Fedora nor rEFInd use the EFI partition to boot the computer. In fact, there is nothing useful in the EFI partition.

Answer to your questions:

How do I uninstall rEFInd 0.8-3.7 using OS X 10.10.3? Read the ./install.sh file and undo whatever it did. I should of had you run the commands bless --info and bless --info --getBoot. These would have told where the .efi file was stored. Note: Almost everyone installs rEFInd to the OS X boot partition.

How would I go and reinstall it using different options if I cannot remove it? The author of the software never said rEFInd could not be removed. I suggested you just install it again to its own partition. This might be a good place to mention the gpt command has to be run while either booted to an external recover partition or while booted to internet recovery.

Could I simply remove the EFI partition or would that corrupt my Mac? Do not remove the EFI partition! It is not used to boot OS X, but it is used by OS X for other things.