From The Stargate Omnipedia
Visions in which Daniel Jackson
recalls moments from his time as an ascended being. During his days of fogginess from retrieving knowledge of his past life, this unique intel became a key asset to members of the S.G.C.
Jackson was banished by the Ancients for breaking their non-interference law, and returned to his physical form with his memory wiped. SG-1 speculated that, because his memories gradually came back, his ascended mentor Oma Desala may have cheated the judgment against him by deliberately making Daniel's amnesia imperfect. Oma later confirmed her involvement.
Orpheus - Daniel Jackson utilizes a flashback to aid SG-1 in disabling the Erebus defense field, and leading a team to free Bra'tac and Rya'c from the death camp.