There is nothing to explain...
Google for "T-MST5DEUC firmware"... and find e.g. this with version 1023:
http://www.samsung.com/au/support/model/PS59D6900DMXXY
Flash that firware using the standard process...
Install SamyGO by following the steps in Wiki...
That's all.
BTW, my TV is currently broken thanks to Samsung's F*CKING automatic Facebook app upgrade... something i NEVER used and NEVER wanted (but couldn't remove since it's "normal" widget, not "user" widget)
It started updating itself, then TV rebooted in the middle of the update... and now it's stuck in boot loop - the Samsung Smart TV logo appears for a second, then goes off and 2 seconds later the TV reboots... and again and again... no chance to do anything with it

Samsung f*ckers...
