At the time, he apologised to the Miles family for raising the possibility of putting them through a re-trial.
"I'm not a murderer and I didn't murder Hayden Miles," he said.
"I made a wrong decision that night and the following morning, and I'll have to live with that for the rest of my life."
Gosnell admitted killing Hayden after a prolonged assault at a Cashel St flat on August 22, 2011. But he denied murderous intent at his trial in April, and asked to be convicted of manslaughter.
The trial had to be halted when a jury member began sobbing over grisly dismemberment evidence. Gosnell cut the schoolboy into 12 pieces with a $20 jigsaw. He dumped the remains in two city graveyards and buried the organs in the backyard.
At sentencing last month, Ms Miles said she had been "living a nightmare that I can't wake up from" since she last saw her son.