I am trying to put this https://github.com/zhelnio/schoolRISCV on vm Linux primary2 5.4.0-113-generic #127-Ubuntu SMP Wed May 18 14:34:18 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux.

There is a line like this in the makefile:
sudo dpkg --add-architecture i386

I end up with a similar thing:
E: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/focal/main/binary-i386/Packages 404 Not Found [IP: 185.125.190.39 80]

I read the article from here https://stackoverflow.com/questions/30316812/ubuntu-apt-get-unable-to-fetch-packages , but it didn’t help as I don’t see anything like this http://us.archive.ubuntu.com/ubuntu/