# Creating USB in macOS

To create bootable USB in macOS we need to download macOS copy first. We can download both online or offline copy.

Prerequisite
- Python (opens new window) 3.10.5 or above.
- Minimum 8GB USB device for macOS 10.13 to macOS 10.15, and 16GB for macOS 11 or above.
- For online installer 4GB USB device is enough.

# Downloading macOS: Offline

To download macOS full installer copy the script and paste in terminal. For Online method - Downloading macOS: Online
- ```
mkdir -p ~/macOS-installer && cd ~/macOS-installer && curl https://raw.githubusercontent.com/munki/macadmin-scripts/main/installinstallmacos.py > installinstallmacos.py && sudo python installinstallmacos.py
```
  Users running macOS Monterey 12.3 or above
  
  Starting from macOS Monterey 12.3, Apple removed support for python2.7, so without it installinstallmacos.py will throw the following error:
```
This tool requires the Python xattr module. Perhaps run 'pip install xattr' to install it.
```
  To overcome the issue, we recommend to install Command Line Tools for Xcode by running xcode-select --install in a Terminal and then run pip3 install xattr.
  
  After that you can run the command below:
```
mkdir -p ~/macOS-installer && cd ~/macOS-installer && curl https://raw.githubusercontent.com/munki/macadmin-scripts/main/installinstallmacos.py > installinstallmacos.py && sudo python3 installinstallmacos.py
```
- we get a nice list of macOS installers.
- If you need a particular versions of macOS, you can select it by typing the number next to it. For this example we'll choose 10:
- This is going to take a while as we're downloading the entire 8GB+ macOS installer.
- Once finished, Click Finder → Shift+Command+G and paste ~/macOS-installer.
- A .dmg containing the macOS Installer, called Install_macOS_11.1-20C69.dmg for example. Mount it and you'll find the installer application.
- Copy the Install macOS x.x.x to Application. (Finder → Shift+Command+A) paste.

# Setting up the installer

Now we'll be formatting the USB to prep for both the macOS installer and Bootloader. We'll want to use macOS Extended (HFS+) with a GUID partition map. This will create two partitions: the main MyVolume and a second called EFI which is used as a boot partition where your firmware (Bootloader) will go.

TIP

By default, Disk Utility only shows partitions – press Command+2 to show all devices (alternatively you can press the View button)
- Select your device → Erase → Name: MyVolume Format: macOS Extended (Journaled) → Scheme: GUID Partition Map
Next open Terminal and run the createinstallmedia command.

sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Other createinstallmedia Commands

# Big Sur
sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

# Catalina
sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

# Mojave
sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

# High Sierra
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Wait until all the files get copied from Installer to your USB device.

# Downloading macOS: Online

To download online installers is super easy, first grab a copy of macrecovery.py (opens new window) extract it open the folder.
Open Terminal, type cd Downloads/macrecovery-V.0.8.2 → Enter.

Copy below script and paste it in terminal.

# High Sierra (10.13)
python3 ./macrecovery.py -b Mac-7BA5B2D9E42DDD94 -m 00000000000J80300 download

# Mojave (10.14)
python3 ./macrecovery.py -b Mac-7BA5B2DFE22DDD8C -m 00000000000KXPG00 download

# Mojave (10.14)
python3 ./macrecovery.py -b Mac-7BA5B2DFE22DDD8C -m 00000000000KXPG00 download

# Big Sur (11)
python3 ./macrecovery.py -b Mac-42FD25EABCABB274 -m 00000000000000000 download

# Latest version
# ie. Monterey (12)
python3 ./macrecovery.py -b Mac-E43C1C25D4880AD6 -m 00000000000000000 download

Once this is done, format your USB as FAT32 with GUID Partition Scheme:
And finally, create folder on the root of this drive called com.apple.recovery.boot and place the newly downloaded BaseSystem/RecoveryImage files in:

# Setting up Bootloader's EFI environment

Setting up Bootloader's EFI environment is simple – all you need to do is mount our EFI system partition.
- Download MountEFI (opens new window), unzip and run MountEFI.command.
TIP

If the file is blocked by Gatekeeper or shows any warning, simply press control and click the file open.
- Type your USB device number, an EFI partition will be mounted on Desktop.
- You'll notice that once we open the EFI partition, it's empty. Here we'll put our bootloader.
- Download your bootloader, unzip it. Copy the EFI Folder on the empty EFI partition.

# Now with all of this done, head to Download your Bootloader to finish up your work

⟵ Creating the USB Creating USB in Windows ⟶