Installer hangs on iMac5,1

Question

Trying to install Ubuntu on iMac5,1 (late 2006 Intel Core 2 Duo).

The normal install ISO doesn't work because of this machine (which seems to be a bit of a lemon) has 32-bit EFI.

I've tried making a DVD-RW (Sony branded) from Matt Gadient's modified installers:

• 20.04 freezes on the Ubuntu spinner
• 20.04 with safe graphics once got as far as the screen below then froze, but normally freezes on the Ubuntu dots after the disc check.
• 18.04 also freezes on the four dots.
• Also tried Mint and it freezes too.

My latest attempt is using Rufus on win10 to put the standard iso onto an external USB disc and then replacing /efi/boot/bootx64.efi with bootia32.efi. Boots much faster but gets stuck at this screen. The external drive is thrashing but the spinner and date have frozen. (This is also what happened once with the modified 20.04 DVD 20.04 when it didn't freeze earlier; I let the DVD drive thrash for two hours before finally powering it down.)

Help?!

Update:

• Unchecking third party software got as far as the user/computer name screen before freezing and thrashing the disc.
• Making the USB disc with Etcher instead of Rufus (and then adding bootia32.efi) produces two EFI boot options in the Mac's menu both of which go to a grub command line.

Update 2:

Tied again with the USB drive made by Rufus and it installed. Don't know what I did different. However,

The 'grub-efi-ia32' package failed to install into /target/. Without the GRUB boot loader, the installed system will not boot

and indeed it did not.

Update 3:

If connected to the internet via ethernet then I don't get the package install error. However, it reboots to a black screen.

Holding down option shows EFI boot for both the internal hard drive and the installer, but if I choose the internal hard drive then I get the black screen.

Following these instructions How can I repair grub? (How to get Ubuntu back after installing Windows?) including the grub-install has made no difference.

Can boot into super-grub2-disc (https://www.supergrubdisk.org/super-grub2-disk/) on USB made by Rufus on win10 but it says unknown filesystem for every partition -- including itself.

Update 4

rEFInd finds two things:

• Boot EFI\ubuntu\grub.efi from EFI System Partition, and
• Boot EFI\ubuntu\grubia32.efi from EFI System Partition.

Selecting the first goes to the black screen.

Selecting the second goes to a menu like on the Ubuntu installer where I can choose either Ubuntu or Advanced options for Ubuntu and you can e to edit the command (I notice (hd0,gpt2) which is the partition on which Ubuntu is installed). The Ubuntu option goes to the black screen. The Advanced... option goes to another menu with four options (two different linux version numbers X recovery mode) and all four go to a screen that says

Loading linux 5.4.0-48-generic ...
Loading initial ramdisk ...
_

both of which I notice are echo commands on the e screen. The keyboard caps lock light flashes then nothing more.

Update 5:

Without rEFInd I can get to the same menu by holding down the shift key. I can add echo statements to the script, so it must be hanging after the end of the script.

Answer 1

I'm actually writing this in Ubuntu 20.04 on an iMac 5,1, though I agree it's an absolute pig of a machine, and I still can't get the WiFi working on it (I'm using a dongle I bought for a fiver to get online).

I don't know how long I've spent faffing around trying to get a version --- any version --- of Linux to run on this recalcitrant computer, but I'm a bit like a dog with a bone, and by God's good grace I got there in the end.

Anyway, my solution came in the shape of this script, written by a capital fellow from Beijing...

https://github.com/mytbk/liveusb-builder

You'll need to clone the ia32efi-test branch, and create an entry for Ubuntu 20.04 --- I just copied and modified the one for 18.04. You can put different distributions on the same USB stick: the iMac will boot them all (sometimes reluctantly). And remember to add radeon.modeset=0 to the GRUB entry, or your boot screen will fade to black...

I've installed Arch (my distribution of choice) this way, too, although I'm stuck with the command line, since it throws a wobbly when I try to run X.

As I say, a pig of a machine...

EDIT: I've now got Arch running X, at last. Thank Heaven...