From his book The Two Truths Debate (which is available for free here):
“Gorampa argues that ultimate truth is ontologically unconditioned, and hence it is not a dependently arisen phenomenon; it is distinct from empirical phenomenon in every sense of the word…it is an absolutely timeless and eternally unchanging phenomenon” (73).
And Thakchoe reminds us that Mipham, the eminent Nyingma-Dzogchen proponent, is in agreement with Gorampa on this (42). In footnote 170 Thakchoe says: “Mipham not only attempts to show that ultimate truth is the only truth but also takes one step further to show that ultimate truth is an absolute, therefore truly existent” (188).
For more discussion on the topic see the IPS Batchelor thread.