Help Never rooted but device status says modified

[Galaxy S3 Help]

I have a Galaxy S3 model number SGH-T999L. I have never rooted and do not wish to be rooted. However, my device status says "modified". I checked the binary counter thing and it says it is normal (CUSTOM BINARY DOWNLOAD: No CURRENT BINARY: Samsung Official). I have backed up and done multiple factory resets, but through the Setting>Back up and reset menu and by holding power+home+volume up. Even after wiping the phone, the device status still says modified. I have heard that using a microSD card can cause this problem, but I tried all the "unmount SD and restart" fixes I found online and none of them worked. I even removed the SD card and did a factory reset without it and that didn't work either. I currently have Android Version 4.1.2 and want to update because a lot of apps are "not compatible". I just want my device to not be modified so I can upgrade my software.

 

[Blu8]

No need to not be rooted or unroot to update a Samsung. You just need to flash firmware using odin. Do you have a windows pc? If so download official firmware from sammobile (you need an account and it's slow as heck, sorry but no way around that).
http://www.sammobile.com/firmwares/download/35794/T999LUVUBNF4_T999LTMBBNF4_TMB/
Download the flashing tool Odin from here: https://www.androidfilehost.com/?fid=24052804347779353

And use it to flash the firmware you downloaded like so: