Just bought a standard/Unlocked DGN2200 N300, very happy with it and I recommend it.
But I dont recommend buying a Telkom locked router and i doubt if the firmware can be over written, refer to this thread. Rather save your self the trouble and buy a new unlocked one for R750 here.
well it is not locked that much I can tell you. I use mine that I got from telkom with afrihost details in it and it works like a charm, but as for loading diffrent firmware. I have not tried so not to sure