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MacOS - Creating Bootable Disk

3 min read

The following tutorial showcases how to burn *.iso image to an external USB drive.

1. Determine The External Disk

diskutil list

The following output prints the available disks on the OS. The one with /dev/disk4 (external, physical): in the end of the output is the attached USB drive.

user@mbp ~ % diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:             Apple_APFS_ISC Container disk1         524.3 MB   disk0s1
   2:                 Apple_APFS Container disk3         994.7 GB   disk0s2
   3:        Apple_APFS_Recovery Container disk2         5.4 GB     disk0s3
 
/dev/disk3 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +994.7 GB   disk3
                                 Physical Store disk0s2
   1:                APFS Volume macOS - Data            547.9 GB   disk3s1
   2:                APFS Volume macOS                   11.2 GB    disk3s3
   3:              APFS Snapshot com.apple.os.update-... 11.2 GB    disk3s3s1
   4:                APFS Volume Preboot                 7.2 GB     disk3s4
   5:                APFS Volume Recovery                1.0 GB     disk3s5
   6:                APFS Volume VM                      3.2 GB     disk3s6
 
/dev/disk4 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *62.7 GB    disk4
   1:       Microsoft Basic Data                         62.7 GB    disk4s1
 
user@mbp ~ %

Be sure not to erase system drive.

Run the code before attaching the USB drive and after the USB drive is attached. Compare the outputs and determine which one is your external USB thumb drive.

2. Unmount The Drive

(assuming, for this example, the USB drive is /dev/disk4 - do not simply copy this, verify the correct path on your own system!):

diskutil unmountDisk /dev/disk4

3. Burn Image to USB Disk

Replace “/dev/diskX” with “/dev/rdiskX” (extra r) to improve the write speeds.

$ sudo dd if=kali-linux-2025.3-live-amd64.iso of=/dev/rdiskX bs=4M status=progress

Troubleshoot

There is a chance you may receive an error when running the above command: dd: invalid number: '4M' or dd: bs: illegal numeric value.
If this is the case, please change the 4M to be 4m.
Additionally, increasing the blocksize (bs) will speed up the write progress, but will also increase the chances of creating a bad USB drive. Using the given value on macOS/OS X has produced reliable images consistently.

Another potential error will be that status=progress does not work on your version of macOS. If this is the case, remove this section and instead use CTRL+T to measure status.

Once dd has finished imaging the drive, it will output something that looks like this:

893+1 records in
893+1 records out
3748147200 bytes transferred in 915.043994 secs (4096139 bytes/sec)

After DD completes, macOS/OS X may try to remount the USB device again. If so, you will get the same pop-up as before. You can safely remove the burned USB external disk.

Reference

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