I'd like to remove rEFInd, since my laptop doesn't wake up from suspension (provided that the laptop is only powered by battery) anymore eversince I installed it (in neither of the operating systems: Mac OS and Ubuntu).

Assuming one has installed rEFInd on the main hard drive, then according to rEFInd's page it should be enough to remove (important: also empty the trash) the following folder:

    /EFI/refind

http://www.rodsbooks.com/refind/installing.html#uninstalling

Indeed my blessed folder is that one:

    Mac:~ user$ bless --info
    finderinfo[0]: XXXXXXXX => Blessed System Folder is /EFI/refind
    finderinfo[1]: XXXXXXXX => Blessed System File is /EFI/refind/refind_x64.efi
    finderinfo[2]:      0 => Open-folder linked list empty
    finderinfo[3]:      0 => No alternate OS blessed file/folder
    finderinfo[4]:      0 => Unused field unset
    finderinfo[5]: XXXXXXXX => OS X blessed folder is /EFI/refind
    64-bit VSDB volume id:  0xXXXXXXXXXXXXXXXXXXXX
    Mac:~ user$ bless --info --getBoot
    /dev/disk0s2

Now my question is, do I have to remove just the `refind` folder, or also the `EFI` folder? Since my `EFI` folder also contains a `tools` folder. Here's the entire folder tree:

    EFI
       - refind
           - icons
           - keys
           - refind_x64.efi
           - refind.conf
       - tools
           - gptsync_x63.efi