this was my fix...
root phone using CF-Auto-Root-m0-m0xx-gti9300.tar
install triangle away
in the list of options is a check box that says
system modified workaround.
tick that box then run triangle away.
when you restart the phone your phone should now say device status normal.
the phone is temporarily unrooted so run software update.
your phone will either update or you'll get a message saying the phone is up to date.
after about 15 minutes goto superSU and unroot the phone.
delete triangle away and superSU in aplications manager.
my phone is still showing as normal.