Step 1

Download macOS Monterey 12.2.1 from here.

Upon downloading install it like a normal application. As a result you will get an icon Install macOS Monterey inside Applications folder.

If macOS is blocking it you need to unlock it in System Preferences -> Security & Privacy -> General pane by clicking Allow button.

Step 2

Insert the first USB stick to any USB port. It must be at least 16 GB in size.

From Finder menu click Go, then Utilites and double click Disk utility icon.

Select your USB stick from the left menu and click Erase button.

Type MyVolume in name field and select Mac OS Extended (Journaled) as format and GUID Partition Map as scheme. Then click Erase button to erase USB stick.

If you can't see Scheme field, click the View widget in the upper left corner of the Disk Utility window and choose Show All Devices. Now you should see your drive device descriptions with the drive name nested underneath. Select the drive description just above the drive name for the device you want to format. After that you will see Scheme in Erase window.

Step 3

Visit https://github.com/alphascorp/Monterey-micropatcher and click Code button then Download ZIP link.

The downloaded file should be automatically unpacked inside Downloads folder.

Step 4

In Finder choose Go, then Utilites and double-click Terminal icon to launch Terminal.

Step 5

Create bootable USB installer by typing a following command (all in one line), then press ENTER:

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

Terminal will ask for password. Type your user password and press ENTER (password won't be shown not even under asterisk).

Creating bootable USB installer will take about 15-50 minutes depending on USB stick write speed.

Step 6

As soon creating bootable USB installer is finished type another commands in Terminal to patch it and press ENTER after each of these (every command in one line):

cd Downloads/Monterey-micropatcher-main

./micropatcher.sh

Step 7

Finally enter such command and press ENTER (all in one line):

./install-setvars.sh

Terminal will ask for users password (it won't be shown not even under asterisk).

Your first USB stick is now patched.

You can now safely remove it from the computer, but it will be needed later.

Step 8

Insert second USB stick and do steps 2, 4 and 5 again to create another bootable Monterey USB stick.

Download https://github.com/dortania/OpenCore-Legacy-Patcher/releases/download/0.3.3/OpenCore-Patcher-GUI.app.zip file (don't use newer OpenCore versions!).

The downloaded file should be automatically unpacked inside Downloads folder.

Go to Downloads folder, right click on OpenCore Patcher file and choose Open.

Step 9

Click Open button to run OpenCore Legacy Patcher.

Step 10

Upon launching OpenCore Legacy Patcher, click Settings icon and check Disable System Integrity Protection, Disable SecureBootModel and NVMe boot.

Step 11

Click Build and Install OpenCore, then select your USB stick and click Continue button.

Step 12

Enter your username password and click OK button to start patching.

Step 13

Finally click Quit button.

Step 14

Reboot your computer.

Press and hold Option key (on Mac keyboard) or ALT key (on Windows keyboard) and click an arrow under EFI boot icon.

Computer will launch OpenCore picker.

Make sure the USB flash drive is inserted into Mac Pro built-in USB hub (front or rear). Extra USB PCIe cards won't show a bootable flash drive.

Step 15

This time click an arrow under Install macOS Monterey to start macOS Monterey installer.

Step 16

If you haven't created blank APFS partition needed for macOS Monterey yet, you can create one now by choosing Disk Utility.

Step 17

If you have APFS partition ready, you can select Install macOS Monterey and click Continue button to start the installation.

Continue macOS installation just like on a supported Mac. The system will reboot several times automatically during installation.

Step 18

When installation is ready you will be presented with Migration Assistant. Leave the default radio button as is and just click Continue button.

Step 19

Now you can move data from your old macOS installation. Click your previous macOS drive and then Continue button.

Step 20

As soon your data is moved you will see macOS Monterey desktop, you need to remove your second OpenCore USB stick and insert the first USB stick contaning Monterey-micropatacher.

Reboot the system.

Press and hold Option key (on Mac keyboard) or ALT key (on Windows keyboard) to see boot picker and click an arrow below EFI boot icon.

Make sure the USB flash drive is inserted into Mac Pro built-in USB hub (front or rear). Extra USB PCIe cards won't show a bootable flash drive.

Computer will be turned off automatically. This will set all proper NVRAM values needed for macOS Monterey. You can now safely remove first USB stick as well.

WARNING: If you would ever reset NVRAM or you have no entry sign then you need to redo this step to be able to boot macOS Monterey.

Step 21

Power on the computer.

Once again press and hold Option key (on Mac keyboard) or ALT key (on Windows keyboard) to see boot picker, then click an arrow under MONTEREY (or other name you've choosed) to boot macOS Monterey. Enjoy!