Visiting the unopened area only with the TTB permit is not enough. Military Permit is additional needed if your itinerary included some military sensitive places, including Ngari (Mt. Kailash, Lake Manasarovar, etc), Nyingchi (Pomi, Rawu, etc.) and some remote places in Shannan area.
Areas Require Military Permit
Ngari: all the places you will visit such as Mt. Kailash, Lake Manasorovar etc.
Nyingchi: all the places you will visit such as Draksumtso, Pomi etc.
Chamdo: all the places you will visit such as Chamdo, Riwoche etc.
Note: If you take a flight to Ngari from Lhasa, Urumqi or Kashgar, you will have to have Tibet Military Permit. Overlanding trip from Sichuan, Yunnan, Xinjiang or Qinghai to Tibet also require Tibet Military Permit.
How to apply for it?
Issued by the Military office in Lhasa, this permit is applied through travel agency before you entering Tibet. Due to a long procedure to get approved, you should provide your scanning copy of valid passport and visa 20 days before leaving for Tibet, if you are planning to travel any of those areas.
