Monterey via "OpenCore Legacy Patcher" on external drive (2012 MBP 9,2)?

[macstatic]

I need to use MacOS 13 Monterey for a little while and wonder if I can install it on/boot from an external USB drive so it won't touch my current OS (10.14.6 Mojave). I'm on a 13" mid-2012 MacBook Pro 9,2.

From what I've read I need to use Open Core Legacy Patcher which I understand takes care of the entire installation, right?

 

[macstatic]

To answer my own question (in case others reading are wondering too)....
I just succeeded in installing MacOS 13.6 Monterey on my 13" Macbook Pro 9,2 (mid-2012) on an external USB-harddrive!

Apart from the Opencore legacy patcher (linked in my previous posting) I needed to have a USB-flash drive (minimum 16 GB as far as I remember -mine was 32GB) for downloading and creating the MacOS installer file to (Opencore legacy patcher also took care of actually downloading the MacOS 13 installer file, so I didn't need to do that separately 👍

As for the external USB-harddrive; I had to reformat it to APFS as it was previously used with "MacOS extended journaled", but within the Monterey-installer I had access to Disk Utility, so I could do it without interrupting the process.