He was radicalised online and had planned to ram a car into a group of people in Christchurch and then stab them. He told police that he'd "done it for Allah".
The teenager has been regularly seeing a judge for judicial monitoring sessions and this year has already admitted three breaches of the intensive supervision order, including two which came after he used his mother's phone to view pornography.
After he was picked up last week, he's been kept in prison.
The jail time has proved a wake-up call, with him telling Judge Stephen O'Driscoll today that he is "not built for prison".
In a heartfelt letter that he penned from his jail cell, the teen said how he'd felt threatened when he walked out.
He hadn't seen his mother for three weeks and was trying to get to her, where he felt safe, he said.
"Please forgive me, your honour," said the remorseful youth.
He acknowledged that "recent events in Christchurch" might have some people worried about him walking away.
But he assured the court that he had promised never to return to extremism.
At an earlier court hearing, he said how the March 15 mosques terror attack had helped him reflect on his own earlier extremist thinking.
After 51 Muslims were massacred in the March 15 mosque attacks, the teen said he felt "disgust", not just for those who died and at how much it has affected the nation, but also disgust at thinking of the harm he himself could've done to "innocent Kiwis" who are "his people".
Judge O'Driscoll last month warned the teenager that if he didn't control his anger and emotions, then he faced being sent to prison.
When he was initially sentenced last year, the Crown had been arguing for a five-year jail sentence. Judge O'Driscoll suggested the teen think about that the next time he gets angry or annoyed.
"Everyone is here trying to help and assist you," the judge told him earlier.
Today, Judge O'Driscoll granted him bail back to his supervised accommodation but warned him he was running out of chances.
The judge thanked him for the impressive letter, opening himself up to his thoughts, feelings and emotions.
But he said, "In the end, actions speak louder than words and you are judged by what you do, not by what you say."
"I'm prepared to give you another chance. I have given you many chances and some would say I have given you too many."
The extended supervision sentence continues and the teen will return for another judicial monitoring session on July 4.
