@alexsh1 Thanks, though I'm not sure you understood exactly what I'm saying.
If I connect the radio to the RPi 3 following the NRF instructions and using the NRF2RFM69 adapter, it is NOT working.

For it to work, I MUST connect the "IRQ" pin of the NRF2RFM69 (which corresponds to RFM's D100 pin) to RPi's pin 22 (which is where CE is supposed to go, according to instructions) and leave CE unconnected.

So if someone is using the NRF2RFM69 adapter and tries to connect the radio to the RPi 3 as if it were an NRF, it won't work. I think this is confusing and that's why I posted it.

First of all, thank you to the creator of this very convenient PCB.
I ordered 10 of those but got confused when I tried to make a RPi 3 gateway and Arduino node.

In the "Connecting the Radio" guide, the instructions are to connect NRF's IRQ pin to Arduino No 2 pin.
This is where RFM's D100 pin is supposed to be connected. As far as I could tell from the PCB this is correct, as RFM's D100 pin is broken out to where NRF's IRQ pin is.

However, in the "Building a Raspberry Pi Gateway" guide, it says to connect RFM's D100 pin to RPi's pin 22, which is where NRF's CE pin is supposed to be connected, not IRQ. As for IRQ, it says it's "optional", but if you do connect it, this should be to RPi's pin 15.

So, if you connect the radio to the RPi following the NRF instructions, you get a different circuit than if you connect it following the RFM instructions (and using the pin matching you get from the "connecting the radio" guide). When I did the former, the gateway wasn't working, but when I did the latter, it worked.

I don't know why this difference exists, but I think it's important to point out for anyone wanting to use the PCB with an RPi.