Returning to the "scrappage" purchases of the early 1990s, the Golf and Foxtrot class submarines were not brought back to operational conditions, but studied. If you have translated the article previously attached to my post correctly, the Krasnokamensk pr.877 submarine completed its last mission on August 30th and was decommissioned from the fleet on September 1st, so it was still considered reliable for carry out that last mission. Procuring an 877 should not have the main function of bringing it back into operation in the North Korean fleet, although with Russian help it is possible and I think they would do it to test it (for example, Myanmar uses an 877 received from India), but having a submarine which is however of a more advanced generation than the Romeo/Type 033 class, a lot of useful information can be obtained regarding the shape of the hull, engine system, silence under water, sensors etc.North Korean is better off with newer 636 boats. 877 is by now kinda equivalent to a dinosaur and God knows how poor it would be in condition after decommissioned.