Pinebook Pro/Truecrypt on Manjaro
At least on the default Manjaro build on Pinebook Pro, as of August 2020 Truecrypt is available in Add/Remove Software.
However it does not work out of the box due to the lack of a loop device needed to mount a Truecrypt volume.
First you need to install dracut
sudo pacman -Syu dracut
sudo echo "loop" >> /etc/modules-load.d/truecrypt.conf
sudo echo "options loop max_loop=8" >> /etc/modprobe.d/eightloop.conf
Make it permanent by rebuilding initrd
You are probably better off installing Veracrypt as described here:-
Original sources of information:-