So after some worries and horror stories, I install a dual boot Pop OS 19.10 (Ubuntu basically) on my Macbook Pro.
If anyone is interested:
- I wrote the PopOS image to a thumb drive using Etcher
- Under Disk Utility in OS X, I resized the apple partition down from 240GB to 170GB
- It wrote for like 12 hours then it hung. I checked the fdisk and it seemed fine so I killed the disk utility.
- I shutdown the computer and inserted the usb from step 1.
- I reboot holding the Option key, and selected the EFI
- It booted from the USB stick
- I selected manage partitions (not Completely remove and install fresh PopOS)
- I created an EFI partition at the end of the disk of 500 MiB (type: Fat32)
- OS X had an EFI partition but it was only 200 MiB which is not large enough for PopOS
- I created a Swap partition of 8GB (8192 MiB): type linux swap
- I created a root partition of the remaining (~69GB): type ext4
- It rebooted to PopOS and I created my account and poof Linux on a macbook
- You sometimes have to boot with the "option key" pressed cause OSX and boot loaders don't play well together.