Forum Discussion
How can I make or create a macOS Sonoma bootable USB installer?
Step-by-Step guide to create macOS Sonoma bootable USB on Windows 10 Home:
1. Format and Partition the USB Drive
Connect your USB drive (at least 16GB recommended).
Use Windows tools like Disk Management or DiskPart to format it:
Open Command Prompt as Administrator.
Use DiskPart:
diskpart
list disk
select disk X # Replace X with your USB disk number
clean
convert gpt
create partition primary fat32 fs=FAT32 quick
assign
exit
The drive now has a GPT partition with a FAT32 EFI partition.
2. Obtain macOS Installer Files
You need the macOS Sonoma installer files, which are typically only available via the Mac App Store.
If you already have access to a Mac:
Download the Install macOS Sonoma.app.
Use createinstallmedia to prepare the installer.
Alternatively, find a macOS Sonoma installer ISO/DMG from trusted sources (note legal considerations).
3. Extract and Copy Installer Files
Mount the installer (on Mac or using a tool like 7-Zip on Windows if possible).
Copy the contents of the installer to the USB drive:
The Install macOS Sonoma.app contains the core files.
You mainly need the InstallESD.dmg or BaseSystem.dmg.
4. Create EFI Bootloader Files
You need to manually create or copy EFI boot files:
Download a minimal EFI bootloader such as rEFInd or Clover EFI (though you wanted to avoid bootloaders, this is minimal).
Place the EFI files in the EFI partition:
Create a directory: /EFI/BOOT/
Copy the bootloader files (BOOTX64.EFI) into this directory.
Configure the startup.nsh or bootx64.efi to point to the installer files.
5. Create macOS Sonoma bootable USB
Ensure the EFI partition has the proper boot files and configuration.
The goal is that when you boot from the USB on a compatible machine, the EFI firmware loads the bootloader, which then loads the installer files.