Flames of Phlegethos (a feat for Tieflings from UA, later published in Xanathar's Guide to Everything) has this ability:
When you roll fire damage for a spell you cast, you can reroll any roll of 1 on the fire damage dice, but you must use the new roll, even if it is another 1.
If you ended up with a 1, can you then apply this benefit of the Elemental Adept feat (PHB, p. 166) to it?
...when you roll damage for a spell you cast that deals damage of that type, you can treat any 1 on a damage die as a 2
You are still using the rerolled 1, you're just treating it as a 2?