Hello,
I installed last Bionic on a Orange Pi PC+. It's on EMMC. (it used to have an old Armbian Ubuntu with 3.x kernel before)
Common settings (background image, GTK theme, icons, panel) are there on logout but are not saved on reboot.
I saved a text file in the home user folder, it's OK.
With another common user I face the same problem, with the root account settings are saved.
My Linux knowledge is average, I really don't know what's wrong.
Thank you
Mathieu