What is documented is his parentage (son of Suppiluliuma I and Queen Henti) and his military annals; Hittite royal records name where kings ruled and campaigned but do not record where royal children were born.
What would resolve this A Hittite administrative or annalistic record naming his birthplace, which none of the surviving Hittite archives supplies.
OpenHittitology; ancient Near Eastern historyItamar Singer; Harry A. Hoffner Jr. (ed.), Hittite Prayers