The "ro" tells the kernel to initially mount the root file system read-only, so it can be checked for defects if necessary.
I mean don't update anything unless you have to, unfortunately the system is very fragile. So you'll have to be very careful, any upgrade or even the installing of some packages can break it, and then you get to keep both pieces.
Usually only a reinstall can fix it, with the possibility that you have to start all over again.