I think the problem is the way the computer is locked, if your computer has a Super Drive, your Mac is automatically configured/locked to boot from that drive and ignore the USB.
Their is no amount of reconfiguration or software tricks that would change that, what you can do is take out the Super Drive, or try cleaning it with a CD cleaner - the one with the brush.
Why not use a bootable USB stick. On the arch-linux wiki there is a tutorial about how to create a bootable USB stick (live USB stick) for OS X:
Taken from the Arch Linux Wiki: https://wiki.archlinux.org/index.php/USB_Installation_Media
On Mac OS X
To be able to use dd on your usb device on a Mac you have to do some special maneuvers. First of all insert your usb device, OS X will automount it, and run
diskutil list
in Terminal.app. Figure out what your usb device is called - mine was called /dev/disk1. (Just use the mount command or sudo dmesg | tail.) Now you run
diskutil unmountDisk /dev/disk1
to unmount the partitions on the device (i.e., /dev/disk1s1) while keeping the device proper (i.e., /dev/disk1). Now we can continue in accordance with the Linux instructions above (but use bs=8192 if you are using the OS X dd, the number comes from 1024*8).
dd if=image.iso of=/dev/disk1 bs=8192
20480+0 records in
20480+0 records out
167772160 bytes transferred in 220.016918 secs (762542 bytes/sec)
it is probably a good idea to eject your drive before physical removal at this point.
diskutil eject /dev/disk1
Creating the bootable USB drive:
Overwrite the USB drive
Warning: This will irrevocably destroy all data on /dev/sdx.
Note: This method does not work with UEFI boot.
Note: Check with lsblk that the USB device is not mounted, and use /dev/sdx instead of /dev/sdx1. These are very common mistakes!
dd bs=4M if=/path/to/archlinux.iso of=/dev/sdx
Note: Some older firmware does not understand the isohybrid hack where start of fake partition offset is 0. See https://bugs.archlinux.org/task/32189 for a fix involving isohybrid.pl.
How to restore the USB drive
Because the ISO image is a hybrid which can either be burned to a disc or directly written to a USB drive, it doesn't include a standard partition table.
After you install Arch Linux and you're done with the USB drive, you should zero out its first 512 bytes (meaning the boot code from the MBR and the non-standard partition table) if you want to restore it to full capacity:
dd count=1 bs=512 if=/dev/zero of=/dev/sdx
Then create a new partition table (e.g. "msdos") and filesystem (e.g. EXT4, FAT32) using gparted, or from a terminal:
For EXT2/3/4 (adjust accordingly), it would be:
cfdisk /dev/sdx
mkfs.ext4 /dev/sdx1
e2label /dev/sdx1 USB_STICK
For FAT32, install the dosfstools package and run:
cfdisk /dev/sdx
mkfs.vfat -F32 /dev/sdx1
dosfslabel /dev/sdx1 USB_STICK
On the wiki there is some more information, for example if you would like to create a boot USB stick from a Windows environment.
Best Answer
I happen to have a 17" iMac 4,1. I burned the
lubuntu-16.04.5-desktop-i386.isoimage to a RW DVD using a 2011 iMac. I booted from the DVD using the 2011 iMac and ran the software on the DVD to verify the DVD was burned correctly.Booting from the DVD using the iMac 4,1 was problematic. Basically, at some point the boot would fail. At least once the boot succeeded. After some research I learned I needed to hit the F6, then include the
nomodesetoption before selectingTry Lubuntu without installing. Once booted to Lubuntu, I could select the install icon on the desktop to start the installation process.My iMac 4,1 has the latest firmware updates which are listed below.
The firmware information can be found under "Hardware Overview" in the System Information application display. Firmware updates for legacy Intel Macs can be downloaded from the Apple website About EFI and SMC firmware updates for Intel-based Mac computers.
Additionally, my iMac 4,1 has 2 GB of RAM installed and has a 1.83 GHz Core Duo (32 bit) processor.