After Marcus Forde and his partner crashed their car and stole the vehicle of a good Samaritan on June 14, they picked up Jacob Forde.
Armed police arrested the group when they stopped at a dairy outside Dunedin, and in the car they found a 9mm pistol loaded with blank rounds and 0.73g of the class A drug.
Jacob Forde was released on bail but he was involved in further serious offending just two days later.
He and 36-year-old Ellery Coffin smoked methamphetamine with their victim outside a fast food restaurant before travelling to Woodhaugh Gardens.
Once there, Forde put his arm around the victim's throat while Coffin punched him in the head and body.
Coffin claimed the man had ripped off his mate - he later said it was over a gram of meth - and then stabbed him just below the eye.
The victim fled to a nearby rest-home while his attackers left the scene, Coffin driving his vehicle away.
The duo drove in convoy to Puddle Alley in Mosgiel, where Coffin ripped out the roof lining of the stolen car and set it alight with a gas torch.
"That's a bit extreme, isn't it?" Forde said.
He later drove Coffin away.
The appeal was primarily focused on the uplift to the prison term that Judge David Robinson imposed for the arson.
"Mr Forde's role in the arson was minor," Justice Dunningham said.
"It was accepted by the Crown he did not anticipate the car would be torched and there was no premeditation."
Because Forde was jailed for 21 months on the violence charge he would serve that entire term without parole, because it represented his second strike.
The three-strikes legislation has since been repealed by Parliament.
