I don't believe the Russians would transfer thermonuclear technology to the North Koreans. Nuclear, yes. Big Stuff, no.
And the Chinese would certainly not do it, they got the destabilization of US interests they wanted with the initial nuclear transfers. Remember, far more damaging to us than even "H-bombs" is deliverability. If the Russians or Chinese were really serious about arming NoKorea the Norks would not be working on improving Scuds; they would already have gotten ballistic missile tech.
The Russians or Chinese might not be serious about actually arming North Korea, hence the lack of ballistic missile tech transfer.
However, they might figure with what is going on in the Ukraine and the South China Sea, North Korea having the H-bomb might be a useful distraction for them, lack of long-range delivery vehicle or not.