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?
Best Answer
Yes, these Feats work together
If you have chosen the feat Elemental Adept and picked Fire, then you can turn a 1 into 2 every time.
This investment in two Feats basically gives you a lower limit of 2 on any fire damage die and you can still use the Feat Flames of Phlegethos prior to that to try and increase the damage beyond that.