Dual boot OS X and Manjaro - Problems (Cross-posted in Linux StackExchange)

So I'm trying to dual boot OS X and Manjaro. Using the graphical installer of Manjaro, you're given the option (well, it's an obligation) to create a partition that mounts to /boot/efi. 

Manjaro installs without any problem and when the Mac reboots it goes straight up into Manjaro.

The thing is I want to make OS X the default boot option and not Manjaro. If I press alt on the Mac Keyboard just after booting (and before it goes into Manjaro) I get to the disk selection screen and I can select OS X fine, it'll boot correctly.

BUT if I try to make OS X as default boot drive in OS X System Preferences and then go to the alt menu at boot and select the manjaro drive it instead goes to OS X...

I even tried this https://wiki.archlinux.org/index.php/MacBookPro11,x#Method_1:_creating_an_extra_apple-format_bootable_partition_with_GRUB in the Arch Wiki and it gets me to GRUB but then Manjaro fails to boot....

What should I do?
My guess would be that OS X is clobbering your GrUB when it sets its own bootloader when you make the change in System Preferences. My advice would be to not set OS X or Monjaro as your default in OS X, but rather use GrUB. You can then set GrUB to default to OS X after a customizable delay, which I assume is the behavior you're looking for. Potentially helpful link