Did my first root of Android phone. I had two Android phones before, but I never rooted it. This time I had a need for root to add the Chinese language to a Samsung Galaxy S3. The specific model is T-mobile SGH-T999 (shown in the Download or Recovery mode, but the model number on the settings says AT&T model number, which caused some issue for me later down the road).
The main reason for doing this is to add Chinese language support. It looks like by reading the article we can only get it work by rooting. I also looked at another article on the language support that suggested both MoreLocale2 and Language Enabler. Tried MoreLocale2 first but it seems needing root. So I started looked at the root tutorial. Because of the “wrong” model number, initially I thought this is an at&t device (model number at&t samsung galaxy s3 i9300, and here is an tutorial for that). Note the two tutorials are similar (t-mobile root tutorial here), the main difference is the at&t one is more verbose, and it has a link to the mod5 file for the at&t model. The odin program did not work for me initially because I was using the latter mod5 file (mismatch between hardware and mod5).
After that mistake the device was stuck in the Download mode (link to get into the Download mode), and could not reboot. I googled I have to download a Samsung software to get it restored. There were other hiccup too, one being the device cannot connect to my Windows 7 laptop (a bit old HP elite book), even after I install the driver. Had to reboot to make sure they connect. Back to topic, I was able to root after I switched to the mod5 file for t-mobile device. And it worked like a charm. After that I installed the rootCheck and SuperSu app from the Play store.
After the root, reboot I installed the Language Enabler app by Wanam from Google Play store (again refer to the language article above).
Final impression: the Samsung s3 is a relatively old device by today’s standard, but it works as a basic smartphone and adding the Chinese language to it, in my specific case, could potentially save an iPhone purchase (SE starts at about $400 in the states). It just takes some work to get it work, from enabling the developer mode/USB debugging on the device, to the odin software root.