The boys, both 14 at the time, watched the film, which featured college students being stabbed, just hours before attacking their 13-year-old friend at a remote beauty spot.
Both denied trying to kill him. But after more than seven hours of deliberations, a jury at Hull Crown Court returned guilty verdicts.
Judge Arthur Myerson adjourned the case for probation and said custodial sentences were bound to follow. Both boys had denied attempted murder. They were remanded in secure accommodation.
Andrew Robertson QC, for the prosecution, said the attack was at a beauty spot near Harrogate, North Yorkshire, in January this year. He said the boys watched the film at the house of a local man, Paul Aurens, before luring their 13-year-old friend to an area called Birk Crag.
At the bottom of a steep slope, the victim said one boy suddenly produced a knife and rammed it into his head. The second boy stopped him getting away and the first continued ramming the knife into his cheek, head and body. The attack only stopped when the victim played dead. He was saved 40 hours later by an elderly man walking his dog.
A hospital surgeon found the boy had suffered 11 stab wounds to his head, three of which went through the skull. One missed a main blood vessel by 1mm. The injured boy suffered a fractured rib, collapsed lung and temporary paralysis on his left side but managed to tell police what had happened.
Mr Robertson said the two boys planned the attack and even brought along a bin bag in which to hide the body.
One boy said he had not been at the Crag that night, while the other admitted being there but blamed his co-accused for the stabbing.
Both denied prosecution allegations that they had obsessive interest in knives and the film, Scream. The victim's family said in a statement that they felt justice had been done and expressed sympathy for the families of both convicted boys.
Detective Constable Simon Mason paid tribute to the police who worked on the case and the people who had helped to rescue the injured youngster. "Some two days after the attack, purely by chance, a witness, Mr George Stephenson, walking his dog strayed from his normal route and happened upon what he thought to be rubbish and two tree logs." Further investigation found the "logs" were the boy's legs.
A man working near by, Mark Ashworth, was trained in fell and cave rescue. "He took immediate control of the situation, alerting emergency services and administered first aid to the victim. It is worth pointing out that the actions of these people saved the life of the victim," said Constable Mason, who also commended the bravery of the injured teenage boy.Reuse content