realwarpdesign wrote:
I'm trying to wipe this machine and install Linux Mint. I have created a bootable drive on a usb thumb drive. I've tested it on other non-apple machines and it works as a bootable drive.
How did you create the bootable Linux Mint USB installer?
On this mac I've tried restarting while holding the option key which hasn't worked.
What exactly has not worked? Were you able to access the Apple boot picker menu at all? If not, then make sure to hold the Option key immediately after hearing the startup chime. Also, use a wired USB keyboard since some wireless keyboards may not go read quickly enough for the special startup keys to register.
If you see the Apple boot picker menu, is there an orange icon labeled "EFI"? If so, that is the Linux boot disk.
I've also tried to select it in the Start Up Disk preference panel but it doesn't show up there.
macOS doesn't understand the drive layout or file systems associated with Linux, so this usually does not work. The Apple boot picker menu is different when you Option boot a Mac since the firmware is looking for a specific file on the drive.
I've also tried the command line using this command
sudo bless --device /dev/disk1 --setBoot --nextonly sudo reboot
This returns an error Could not set boot device property: 0xe00002bc
It is very difficult to use the "bless" command on non-Apple file systems, plus the Linux USB installer is most likely read-only. IIRC, the "bless" command needs to set a flag/file on the "blessed" volume/drive. You would need to specify the partition containing the bootloader, but perhaps even the "boot" folder for the bootloader. Many times the USB installer will have two "partitions" which complicates things as well. Even if you issue the command correctly, this is unlikely to work for the Linux USB installer.
How can I boot from this external thumb drive?
Option Booting is the only reliable method as is using a wired USB keyboard. Pressing the special startup keys too early or too late will cause them to be ignored....timing is crucial. In fact holding the keys too early can prevent the Mac from even attempting to "boot" to anything until the keys are released (varies by Mac).
Did you also create a bootable macOS 10.13 USB installer as well so if you ever decide to reinstall macOS that you have a way to do so since many people find Internet Recovery Mode does not always work as intended.....especially for older hardware & older versions of macOS. I highly recommend doing this now while you still can. I see so many people on this forum wanting to reinstall macOS later & having difficulties with Internet Recovery Mode.
Create a bootable installer for macOS - Apple Support
