The claims by Buk manufacturer Almaz-Antey were debunked already in 2015 by Bellingcat.
The Joint Investigation Team has concluded that flight MH17 was shot down on 17 July 2014 by a missile of the 9M38 series, launched by a BUK-TELAR, from farmland in the vicinity of Pervomaiskiy. At that time, the area was controlled by pro-Russian fighters. The BUK-TELAR was brought in from the territory of the Russian Federation and subsequently, after having shot down flight MH17, was taken back to the Russian Federation.
On 24 May 2018, JIT stated that the BUK-TELAR that was used to down MH17 originates from the 53rd Anti Aircraft Missile brigade, a unit of the Russian army from Kursk in the Russian Federation. The JIT reached this conclusion after extensive comparative research. An animation of this comparative research is available here.
The European Union and NATO have called on the Russian Federation to accept its responsibility and to fully cooperate with all efforts to establish accountability. On the basis of the JIT’s conclusions, the Netherlands and Australia said that they are convinced that Russia is responsible for the deployment of the Buk installation that was used to down MH17.
More cases on MH17 flight here.