Just wanted to share that I started with a clean install of Raspberry Pi )S 64bit and when I went through the steps for “enabling multiplexing on the raspberry pi serial interface” I ran into a snag. In step 3. Download kernel source, it requires python2.7, apparently the OS did not come with Python2.7 installed. Using python –version and python3 –version returned the same version of 3.9.2. The library urllib2 is not available in Python3 from what I read on stackoverflow. So to solve this issue, sudo apt-get install python2.7 got me going again.