> That means it's probably "only" a few hundred kilotons depending on depth. 8/ Still a staged TN weapon. But I need to sleep. 9/
https://twitter.com/ArmsControlWonk/status/90419708681554329...
I just found this too (from 2016), which backs up what you're saying
https://www.wired.com/2016/01/science-can-tell-if-north-kore...
It seems according to that, you could only tell from the radionuclides emitted as to what type of bomb it was.
Interestingly there was a 500kt fission bomb - https://en.wikipedia.org/wiki/Ivy_King (but I assume experts must have a particular reason for thinking the DPRK detonation was a type of hydrogen bomb).