[Guide] DoCoMo SC-03E Samsung Galaxy S III alpha, How to change Tethering preset APN

This work has been edited collecting many info taken from many guides on-line… and tested by me.

A well known issue after SIM-Unlocking the SC-03E, is that you can’t change the APN on your own provider’s APN when you want use the Tethering.

Even if you set your provider’s APN in the APNs settings, when you switch on the Wi-Fi Tethering the APN automatically sets itself on a specified DoCoMo APN (dcmtrg.ne.jp) to check your data traffic by your PC.

So, if you decide to use a no-DoCoMo SIM Card, you can’t use your smartphone as modem for your PC.

There are 3 ways to get over this problem, but in all of them you need a rooted ROM (so, be careful at what you are doing).

If you need to keep a DoCoMo ROM, at present the only Rooted “DoCoMo” ROMs working for this job are the ROMs from aki0306.
You can find them here.

If you don’t need a DoCoMo, you can choose a Custom ROM as the CyanogenMod10.1 JP Remix for SC-03E.

Thaks to kizuki.buy and theDroidfanatic for some tips.