Hi.
I'm using a GD77 in hotspot mode too.
It's connected to a Pi3 using PiStar and works (mostly) fine.
The one thing not working is the adjustment of power levels.
The SW-102 shows the same rating (1W) when setting RFLevel=99 and RFLevel=1... .
Tested several other levels, it's 1W every time.
1W is fine for me, but I'd love to understand why the GD77 doesn't switch the levels.
Using the GD77 without hotspot mode the power levels can be switched WITH impact to the actual power delivered.
73, Christian, DO1BBQ