The takeaway is that Mac natively makes bootable installers.
- Format USB as macOS Extended (Journaled) – Erase entire media, fill in name, MacOS Journaled, GUID partition
Even though the M1 requires its internal SSD to be APFS to boot, the bootable USB has to be macOS Extended (Journaled). Here’s what Google AI Mode had to say about that:• The External USB Installer: A bootable USB installer is not a standard operating system drive. It is a specialized execution disk. Apple's internal createinstallmedia tool is historically hardcoded to write its data blocks onto a Mac OS Extended (Journaled) platform.• The Automatic Handshake: When you point the Terminal tool to your Mac OS Extended USB drive, the script will write the installer files natively. Then, during the creation process, it will automatically wrap the boot container in a specialized structural hybrid format that the M1 chip's security firmware recognizes instantly as a valid external boot launchpad. You must format it as Mac OS Extended (Journaled) to start. - Create the bootable USB. Will ask for password. Fill in the USB’s name:
sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/USBname
The USB will be renamed:
Install media now available at “/Volumes/Install macOS Ventura”
3. Check to verify a good copy. I did this with shasum but I can’t recreate right now exactly what I did. I usually get kind of wound up at this point and don’t document that well.
4. Exit status of most recent command. — no errors.
echo $?
0