To answer my own question, having spoken to Dlink support:
- Yes, 2.10B02 is a successor to 2.10EN, and is specifically meant to work on a DAP-1360B01.
- The ONLY info readily available for these firmware releases is what is on that dlink download page, so no changelog, and no previous versions (or their relnotes).
- They suggested a "Crash reset" (I think that was the term) where instead of doing as the manual says for a factory reset, do this: pres/hold the reset button for 10secs... disconnect power for 30secs... reconnect power and after 10secs let go of the reset button. Then try firmware upgrade again. If that doesn't work, the unit is returned DOA.