💽 Bootable USB Creation on macOS (no third-party apps required)

This repository provides a simple, generic, and reliable guide to creating a bootable USB drive from any ISO image using macOS Terminal.

Whether you're preparing a Linux installer, a Windows setup, or a custom live system, this method works without Boot Camp, without Etcher, and without any GUI tools — just native commands and full control.

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🧰 What You’ll Need

• A USB drive (8 GB minimum recommended)
• A valid .iso image (Linux, Windows, etc.)
• Access to the Terminal and admin privileges (for sudo)

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⚙️ Step-by-Step Guide

1. Insert your USB drive and identify it

Open Terminal and run:

$ diskutil list

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:             Apple_APFS_ISC Container disk1         524.3 MB   disk0s1
   2:                 Apple_APFS Container disk3         494.4 GB   disk0s2
   3:        Apple_APFS_Recovery Container disk2         5.4 GB     disk0s3

/dev/disk6 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *15.4 GB    disk6
   1:                        EFI EFI                     209.7 MB   disk6s1
   2:       Microsoft Basic Data LINUX                   15.2 GB    disk6s2

Note

This will list all available disks. Look for your USB drive — e.g. /dev/disk2, /dev/disk3, etc.

Caution

Double-check the disk identifier. Writing to the wrong disk can erase your macOS system.

In this example, the USB drive is: /dev/disk6

2. Unmount USB drive (don't eject it!)

$ diskutil unmountDisk /dev/disk6

3. Use dd to write the .iso to the USB drive

$ sudo dd if=/path/to/your.iso of=/dev/disk6 bs=1m status=progress

Let’s break down the important options used here:

• if= (input file): This specifies the path to the source file, which is the ISO image you want to write to the USB drive.

• of= (output file): This specifies the destination device to write to, in this case your USB drive. It’s important to use the full disk device (not a partition), e.g. /dev/disk6

• bs=1m (block size): Sets the size of each read/write operation to 1 megabyte (1m). Larger blocks reduce overhead and speed up the process.

• status=progress: This option makes dd display ongoing progress information, such as the number of bytes transferred, which is helpful since dd is usually silent.

4. Wait for the operation to complete

The process may take a few minutes depending on your USB drive and port (USB 2.0 vs 3.0). At the end, you’ll see something like:

5242880000 bytes transferred in 220.123456 secs (23823092 bytes/sec)

5. Eject the USB drive safely

$ diskutil eject /dev/disk6

You can now remove the USB stick and use it to boot on another system.