I want to install Ubuntu Gnome 17.04 on a USB pen drive which has a microswitch to make the USB pen drive hardware-protected read-only. My plan is to use the USB pen drive read-only in combination with several other USB pen drives with UnionFS (for every not trustable app there is a new USB pen drive). However, I want also to use the USB pen drive in read-write mode (without another USB pen drive attached) to update Ubuntu.
How can I achieve this?
I made two attempts, which failed:
installed Ubuntu on USB pen drive; It didn't booted in hardware-protected read-only mode.
made Live-USB with Ubuntu Startup Disc Creator on USB pen drive with 4GB persistence; I couldn't update Ubuntu.