John Kafunda, 22, and Reece Donovan, 22, were both convicted of violent disorder, the Evening Standard reported. Kafunda was found guilty of robbery and Donovan of theft and burglarizing a Tesco supermarket.
Investigators said the pair pretended they were helping Ashraf Rossli, 19, who suffered a broken jaw in the earlier attack. But a security camera captured them taking a Sony game console from his backpack.
Rossli said he was attacked as he bicycled to the home of a woman friend who had called because she felt unsafe during last summer's riots. He said he was punched as he tried to see who was grabbing his cellphone.
"Blood was pouring from my mouth and I could feel it running on to my hands," he said. "I was disorientated and confused. I remember my bike being taken. I knew they were stealing from me but I could do nothing."
Kafunda and Donovan were jailed after the verdict. They are scheduled to be sentenced next week in Wood Green Crown Court along with Beau Isagba, 17, who was found guilty of the first attack on Rossli.