Razer Mamba Hyperflux + Razer Firefly Hyperflux Not Working

Greetings!

I picked up a used Razer Mamba/Firefly Hyperflux combo for my kid but there is a problem:

1) Mouse works when wired (means mouse itself and the USB cable both work fine)
2) Mouse does not work when wireless: mouse LEDs all light up (so, there is power) but the mouse is dead (cursor and buttons). The pad LED is green, but mouse powerLED is white (I would expect them to match in color)

Mamba S/N: (*Omitted)
Firefly S/N: (*Omitted)

Pictures: (*Omitted)

To get the obvious out of the way:
1) Firmware updated to the latest version (1.02)
2) Synapse3 up to date; Win10 rebooted and up to date
3) No metal or routers (or any other sort of interference) around

Question: is it possible to convince my Mamba to talk to the Firefly? If not, anything else I can try?

(the pad looks amaizng in the dark, and he mouse works great when wired -- it'd be a shame to lose either)