Getting Octopi and Klipper working

Installing OctoPi and Klipper where I am was a little more problematic as it appears that I have some firewall issues and I cannot be bothered with VPN. So I had to modify the sources.list and raspi.list files for the apt-get to point to mirrors that I could access; which were in:

/etc/apt/sources.list

# deb http://raspbian.raspberrypi.org/raspbian/ buster main contrib non-free rpi

deb http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ buster main contrib non-free rpi

# Uncomment line below then 'apt-get update' to enable 'apt-get source'

#deb-src http://raspbian.raspberrypi.org/raspbian/ buster main contrib non-free rpi

/etc/apt/sources.list.d/raspi.list

deb http://ftp.cn.debian.org/debian/ buster main

#deb http://archive.raspberrypi.org/debian/ buster main

# Uncomment line below then 'apt-get update' to enable 'apt-get source'

#deb-src http://archive.raspberrypi.org/debian/ buster main

Links to the two mirror sites: Raspbian mirrors and Debian mirrors. I ended up using http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ and ftp.cn.debian.org/debian/ based on my current location. Please check different mirrors that best suit your own location.

Finally, I had the last problem of the public keys and had to run this before I could run the install scripts:

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys KEYGOESHERE