You have to read them in order to understanding Augustine Christian evolution. Once Augustine understood that it was by grace he was saved, he recalled some of his works to be burned. This is written in the final writings of Augustine.
Augustine came to understand that we are saved by grace and grace alone. He championed this through the Council of Orange decrees to fight against Pelagius and Semi-Pelagius. The Council of Trent has ignored the Council of Orange’s decrees favoring a Semi-Pelagius view (though they will deny it). The synergistic view of the Council of Trent all but ignores the early church father’s writings.
Shall I point you to some passages in the Catholic Encyclopedia that states the church fathers were mistaken, didn’t fully understand, etc.?
He didn't burn anything. Shortly before his death, he examined some of his earlier works, yes, as Possidius tells us and the Retractations are still available to read. I haven't read them and they are hard to find online but I'll bet you there isn't anything in there that repudiates his earlier views on the episcopacy the Mass or anything else I mentioned.
Also, think it through...if he repudiated his Catholicism, why did Catholics canonize him and venerate him?