The ruling will be appealed, lawyer Jānis Mucenieks told LTV.
It is unclear how long it will take before the sentence is translated and a subsequent appeal submitted, but it may take several weeks, Mucenieks told Latvian Radio.
Bērziņš has spent the last five months in prison.
He has been convicted for participation in the 2009 riot in Riga but fled Latvia to avoid serving his sentence of one year and eight months, which was regarded as too harsh by some people.
During an online news conference via Skype in July 2016, Bērziņš announced that he felt let down by the Latvian state. As a young boy, he had actively participated in the drive for Latvia's independence but now the Latvian authorities want to put him in jail, he complained.
However, he did not deny that he had been throwing cobblestones at the Latvian parliament building during the riot, which soon afterwards contributed to the collapse of the government. Bērziņš said he had left the country to avoid going to jail but would not say in which country he was staying currently.
On January 13, 2009, a peaceful protest against the government turned into a riot and over 50 rioters have been convicted, although only nine were given real jail terms. The conditional sentence given to Bērziņš by the court became a real jail term after he failed to register with the State Probation Service, which was one of the conditions of his conditional sentence.