"Bootable" flash drive on macOS does not appear as a start-up option

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1

I want to boot Fedora from a flash drive before deciding whether or not to install it on my computer.

I used Fedora Media Writer to make a USB flash drive bootable on my iMac (macOS, Sequoia, 15.5). I had it use Fedora-Workstation-Live-42-1.1.aarch64.iso. The process seemed to be successful.

When I re-started the computer and brought up the start-up options, where I should be able to select the start-up disk, the flash drive does not appear. Only the internal drive appears.

I copied the Fedora files from the flash drive, re-formatted the flash drive in APFS format with a GUID partition map, which I believe macOS needs on a bootable drive, copied the Fedora files back onto the flash drive, and tried again to boot from the flash drive. Same result.

What am I missing?

2

Hi and welcome to :fedora: !

There is no need to format the USB in APFS format. I assume Fedora Media Writer will reformat it anyway.

What generation of iMac is it you’re trying to install Fedora on? I would verify a couple of things.

First and foremost, it should be an Intel Mac[1].

Then make sure Mac’s built-in System Integrity Protection is not preventing to boot from USB. There are loads of resources describing how to temporarily disable System Integrity Protection (e.g. here).

Finally, you could make sure it’s not an issue with the created media itself, by testing it on a PC.

  1. If it’s a Mac with Apple silicon, have a look at the Asahi project. ↩︎

3

Many thanks for the welcome and the quick help, Mike.

It’s Apple Silicon. I did not read anywhere that only Intel Macs are supported. I’ll check out Asahi.

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4

Give yourself enough time to go through the Asahi documentation. AFAIK, there is no way to test it before installing though, as one does with a live ISO.

If you’ll encounter issues, you can come back here, but post your questions in the Ask Asahi section (in case they are Asahi related).