History
2015: Cooling fans bad. HD 'erased'. Booted fine from Ubuntu CD.
2019: Repart'd adding Mint18. Perfect until...
2020: FireFox self-destructed. Chrome installed (no auto-updating).
2022: Chrome died to 'adver-titis' Kudos to very old Midori !

2023: Repart'd clearing Ubuntu for Mint21 install.
note: I don't remember any mentions about GRUB or a UEFI partition.
MINT21 was sooo slow !!! Copying files from Mint18 to Mint21 was a Snail !
Had to USB boot to rescue GRUB allowing Mint18 to boot.
Obviously, the old Mac doesn't like this screwy set-up.

Today, I USB-booted MXlinux(64)ISO and it performed better than old Mint18.
However, the install-step(Gparted) insists on re-formatting ALL partitions.
Thats 1999 silly,,,like 'Zorin',,,Its easy to replace XP, just erase it !

How do I install a 64 bit OS into partition X ?
Sans, No automatic or 'custom' formatting.

All help & comments welcomed.
I have no APPLE / MAC / BIOS software.

Linux installers generally give the user 3 or more options. Erase and install, install alongside (if any other OS is detected) or a manual installation. In a manual installation, the user selects a specific partition on which to install and should be given the opportunity to format or not.

Macs have been using UEFI for over a decade so posting some info on the age and hardware of the computer might help someone to help you.

Could you be more specific about what exactly happens and your drive/partition setup currently?

Latest MINT and MX are 64bit EFI ONLY, and thats the problem on my MAC.
It is now dead. Power ON to blank-white screen.
The MX distro DVD is 'jailed' inside,,, No bios means No eject.
Refuses to boot from any USB flash/HD/CD/DVD devices.
The arcane keyboard commands do nothing.
I believe its time for a lobotomy.

My no-buttons fonny connects to Gmail.
What else would a deaf 80yr old need ?

The MAC, as I remember, was the all-aluminum big-screen Intel 'Duo'. Circa 2015.
It cost more than my first Ford !

Thanks for your input ;>)

Try Power Off, hold the 'Option' key, then Power On.
Be patient until you see the CD/DVD symbol then try to boot from that.
Mine is much older and boots from CD/DVD only. No problem with MX, just choose option that erases everything.

Thanks for the info

Best try was power-on, then keys Option + Apple + F + O
(ALT key is Option, Windows key is Apple, and yes, it takes both hands)
(also tried Option + Apple + P + R)

It doesn't boot, but is resets the framitz and the doflop, and finally goes to a black screen.
(no keyboard,, just black screen !)
NOW, power-off, then power-on, then hold Option key, till it 'acts busy'.
(I have a useless USB plugged in, ONLY so I can associate the red blinks with the booting.)

Finally, got it to boot from the original MINT19 DVD ! (No EFI crap)
Gparted to delete all partitions, except the old MINT19 which used old GRUB.
Again, power-off, then power-on, then hold Option key.
Boot the DVD, run the INSTALL first, creating a new MINT19 partition & new GRUB.
Eject the DVD.

Now it boots from the HD,,, sorta,,, Mac & GRUB dis-agree on screen resolutions.
When/IF that happens, Power-off & try again.

Whatever MXLinux w/EFI did to the Mac BIOS has left it damaged.
The HD now contains a new 'bios-grub' partition.

Currently, I am moving some 60GB off to removable disk(s) as I cannot rely on the Mac.
This entire fiasco started when Firefox puked, Vivaldi aged and died, then Chrome 'auto-updated' itself into oblivion.
So I installed the latest MINT21. Never did get it to boot.
Was advised to try MXlinux, on a laptop. It was fine running from DVD, but HD install re-formats entire HD.

I have two more Macs in the barn, I'll install MXL on one and see how it goes.

Many thanks for your response.

Yiik...
Let's us know how thing goes.

I have tested and found a work-around... to make this short, read the following email to India, about the Ubuntu ZINC distro.

Two days passed since my email about installing ZINC on iMAC PC, without UEFI, alongside 2 MINT (grub booted).
The consensus says; It simply cannot be done, without re-formatting the ENTIRE hard drive..
I have found a very simple solution. install ZINC on a second hard drive, letting it default to UEFI..
The ZINC installer will also copy-over your most recently used folders, documents, photos, etc.into the new desktop.
Somehow, it “merges” into the existing GRUB MINT1+MINT2 structure. On top,,, ZINC(uefi)+MINT1+MINT2(grub).
The trick is, iMAC always boots from the prev boot, so you must manually select newHD, or oldHD at power ON.
Only one problem so far. Re-starting from hibernation gets lost in ‘video-land’ ;>)
ZINC comes back to life, but video appears to have lost synch, size, and color. Suspect odd iMAC video driver.
We will continue ahead using ZINC for another few years to complete a very long re-programming project.
Appreciate your interests. END.

I have another iMAC ! Bigger screen ! Sata HD ! Quiet !
NEW installs MacOS-12.6 + Manjaro-22.1 + MINT-20 + userData partition..

The old iMac had over-heated for the last time, and retired to the barn.
My up-grade plans went to the trash, along with half-dozen "newest" distros. Mint-20 was the ONLY survivor !

I used Manjaro years ago when involved with a Banyan-Vines conversion.
This new Manjaro with the xfce desktop implementation is my favorite,
Other than small quirks with the Apple???graphics processor, no problems have been found.

Examples: iMAC screen 3840 x 2160 = 163 DPI = 8.3 MegaPixels
Linux comfy settings 1920 x 2160 = 84 DPI = 2,3 MP

Try to read the GRUB boot menu at 163 DPI. Its 8mm tall ;>)
I don't speak GRUB.. can I somehow fake "VGA" ?
Any help is appreciated !

Now running Debian(12.) with Q4os(5.0) which includes KDE/Plasma/Trinity desktop.

Had to let go of some good, and some favorite programs (read; no longer supported).
This new Debian 'bookworm' is a speed-demon,,, in a speed-boot-race, they were always the slowest !

It has no problems with sharing the machine with AppleOS partitions.
Clarify: Security rules: They do NOT share data, but with a small FAT'mailbox' partition, I write/read/delete a file which Apple can read-only.
Likewise, Apple can w/r/d which Linux can read-only.

The Q4os desktop has no problems with Apple's video. Finally, a hi-res screen I can read without squinting !
The screen layout is perfect, I'm still discovering little things like "Peek at desktop" !
Plus important things like the Menu includes A,B,C,D,,,Z as quick index.

Q4os stripped of Chromium, LibreAwfice, and a world of "K-" software, is a rocket !
I added Falkon fastest-browser (easily handles 6 windows), and POLO file manager, the only one that does not bite

Q4os ++++ 4stars. Everything seems there, and working,,, I had to supply a few passwords, and that's it !
Contrary to some opinions, it has not said anything in German ! Documentation is all on-line.

My Epson multi-device is on a USB cable. The WiFi/CUPS connection is a waste-of-time.
Back when we ran old MINT it worked. None of the new distros were successful.

That's it for now, time to go fishing.