I've updated the "Mount_WaydroidHome.sh" script, so the WaydroidHome folder is writable from Ubuntu Touch (without using sudo):
#!/bin/bash
## Set-up commands
#mkdir ~/WaydroidHome
#chmod 755 ~/WaydroidHome
#sudo chmod 777 ~/.local/share/waydroid/data/media/0
## Bind mount Waydroid's home folder if it's not already mounted, and then ensure it (and all sub-folders) stay read/write-able by the Ubuntu Touch user
set -e
/usr/bin/findmnt -rno SOURCE,TARGET /home/phablet/WaydroidHome >/dev/null || /usr/bin/mount --bind /home/phablet/.local/share/waydroid/data/media/0 /home/phablet/WaydroidHome
while /usr/bin/true; do
/usr/bin/sleep 5
if [[ ! "$(/usr/bin/stat -c "%a" /home/phablet/WaydroidHome)" == *7 ]]; then
/usr/bin/find /home/phablet/WaydroidHome -type d ! -perm -o+rwx -print0 | /usr/bin/xargs -0 -I {} /usr/bin/chmod o+rwx '{}'
fi
done
WARNING: The above scripts work for me, but I haven't tested it thoroughly, or even for that long, and it may contain security flaws. It is (as I said before) just a 'quick hack'. In the spirit of open source, I hope other people will provide improvements to it.