iMac Linux

Getting Linux on this old iMac was a bit of a bear, but I've learned some things in the process, I'll share them here for anyone who might be trying to do the same thing and/or myself in the future.

Some general points:

• Macs (iMac or otherwise) from different years can be much simpler to setup with Linux, compatibility problems are not consistent. This info is specific to my iMac model (mid-2010) but may be useful for other models.
• Ubuntu and Elementary (an offshoot OS) have a lot of built-in support for Mac hardware
• My issue was having to do with the boot up process, iMac's non-standard UEFI (so much for the U) and understanding how to work with Grub.

Below is a compiled transcript of what I did in a general sense. In reality I ended up giving up with installing just Elementary, and changed tactics to see if Ubuntu would be simpler. I ended up getting the boot process working with Ubuntu, however if I was starting over, I believe I could have done the same with Elementary. In the end, I decided to keep Ubuntu because Elementary allowed me to adjust the partition with an easy to use GUI so I could run them both. If you're trying to get just Elementary running, I don't think you'd need to do this.

Here's the transcript:

• You'll want a USB flash drive, and wired USB keyboard and mouse.
• Setup flash drive with ISO for installer, using Balena Etcher for example
• Put flash drive in the Mac
• Boot Mac holding "Alt" to get EFI boot picker, pick the flash drive (if two show up, either one works).
• As you see the boot screen, press an arrow key to stop the timeout
• Press 'e' to enter grub's option mode
• Add the word 'nomodeset' at end of the line that has the word "splash"
• F10 or CTRL-x to boot
• Pick "Install Elementary" and follow the prompts

After this, I'm prompted to remove the flash drive to restart, but it boots into a black screen. So we repeat the process, but this time we pick "Try Elementary" so we can get into a working OS (running off the flash drive). Then we'll do our boot modifications to the main install from this temporary one.

• Shut down computer
• Put the flash drive back in and power it up
• During boot up hold "Alt" to get EFI boot picker, pick the flash drive (if two show up, either one works).
• As you see the boot screen, press an arrow key to stop the timeout
• Press 'e' to enter grub's option mode
• Add the word 'nomodeset' at end of the line that has the word "splash"
• F10 or CTRL-x to boot
• Pick "Try Elementary" this time, to boot into the live USB OS
• Open terminal from applications

	sudo -i  

to work as root user

	fdisk -l

to see what the drives are, find the one who's size is measured in Gigabytes (e.g. /dev/sda2). Now we are going to mount that main drive and associated OS folders so we can apply changes.

	mount /dev/sda2 /mnt/
	for i in /dev /dev/pts /proc /sys /run; do mount -B $i /mnt$i; done
	cd /mnt

Now we chroot to emulate like we are operating in the main OS drive.

	chroot /mnt
	pico /etc/default/grub  

to edit the grub file, add 'nomodeset' after "splash"

	CTRL-X 

to exit, choose "y" to save when prompted. Next we run "update-grub" so the changes will stick.

	update-grub

Restart computer. You may be done now, but if you're thrown into grub prompt, then:

	ls 

to see the drives e.g. (hd0) (hd0, gpt2), (hd1)... or something like that

	ls (hd0)

to see what type of drive it is, look for the super large ext* one. Note "(hd0, gpt2)" is a fake example name.

	set boot=(hd0, gpt2)
	set prefix=(hd0, gpt2)/boot/grub
	insmod normal
	normal

This should get you booted in. Then open terminal and

	sudo -i
	grub-install /dev/sda2
	apt-get udpate
	apt-get upgrade

Now you should be able to shut down and restart as needed.

The above is a pseudo transcript of what I (sort of) did. If you have updates or additional info you think should be added, let me know and I'll add notes.