Trouble building older version of ArduPilot

Hi I’ve been working on downloading on older edited version of ardupilot (here) from GitHub. I used this process to load the current master version in and it worked fine. Whenever I try and do the same with the older version I get an error when trying to load submodules. Using the command git submodule update --recursive as the root user I get the error below.

I have tried using git submodule update --recursive --force as well and still get the same error. I’m running Ubuntu 18.04 on a windows 11 pc.