Thanks for the info, that's great! I got the armhf version working under a 64-bit OS install, by using the install script available from wolfram. Since I'm running Kali, and not Raspian, the apt install wolfram-engine won't work for me, I'll need to find a way to actually download the .deb file similar to the way the install script found at -engine-raspi-install does.
Also, the install script installs two parts, wolfram-engine and wolframscript, I assume they are both 64-bit, otherwise it's still a mixed 32-bit/64-bit installation, which is somewhat less efficient when it comes to shared libraries being loaded twice into memory, once in a 32-bit and once in a 64-bit version. I guess I'll need to dig for the download URLs of these arm64 deb packages, unless someone here has them handy.
I just ran on a Buster card:sudo apt-get updatesudo apt-get upgradesudo apt-get install wolfram-engine and it worked flawlessly.There is also a menu option (I forget precisely where) to install recommended software and it will install Mathematica. I did have timeouts with downloads of the Buster image, so it must be popular, and with some updates. I've spent much of the past few days experimenting with Jessie (Mathematica 10), Stretch (Mathematica 11) and Buster (Mathematica 12).
I've spent much of the last few days exploring Mathematica on the PI, using archived versions of Jessie, Stretch, and the new Buster. I was looking at benchmarks across my 3Pis and versions. I learned Jessie runs Mathematica 10, Stretch runs Mathematica 11 & Buster runs Mathematica 12. I'm surprised at the trouble people are having, after burning a Buster card I just ran sudo apt-get updatesudo apt-get upgradesudo apt-get install wolfram-engineand it worked without a hitch.
 38c6e68cf9