The United States Court of Appeals for the First Circuit ruled to overturn his death sentence on five counts, saying the judge made several mistakes.
The convictions on three of the counts Tsarnaev was convicted of have been overturned, the three-judge panel said.
But Tsarnaev does not get out of federal prison.
“And to be crystal clear: because we uphold the convictions (excluding the three convictions in paragraph 924 (c)) and the many life sentences handed down on these remaining counts (which Dzhokhar did not contest), Dzhokhar will remain in prison for the rest of his life, the only remaining question being whether the government will end his life by executing him ”, says the opinion, written by the judge of the Court Ojetta Rogeriee Thompson.
Tsarnaev is being held in a federal prison in Colorado. He was sentenced in 2015, including the deaths of Krystle Campbell, Martin Richard, Lingzi Lu in the marathon and police officer Sean Collier.
Tsarnaev was 19 when he and his brother, Tamerlan, then 26, traveled to Boylston Street in Boston shortly before 3 p.m. on April 15, 2013, to complete their plot.
Surveillance video showed the brothers carrying the pressure cooker bombs in backpacks and moving through crowds near the marathon finish line in what federal prosecutors called a coordinated attack.
Tamerlan set off the first bomb, a 6-liter pressure cooker containing gunpowder, nails and marbles, prosecutors said. The bomb killed Campbell, a 29-year-old restaurant manager, and permanently injured several others who lost their legs.
The second pressure cooker bomb, carried by Dzhokhar, exploded 12 seconds later and killed two people, Martin and Lu, a graduate student from China.
The shelling sparked a manhunt for days that closed the city. The brothers, while on the run, killed police officer Sean Collier of the Massachusetts Institute of Technology. After stealing an SUV, the two were chased by police.
Tamerlan died in an explosive shootout with police near Watertown. Dzhokhar was arrested a day later.
CNN’s Mark Morales and Steve Almasy contributed to this report.