Tom

I'll chime in with my disappointment as well with the lack of followup on a number of issues posted in the forums. Really do have to wonder what future the netduino platform has, and if SecretLabs is a one-man-show? 
I know MS have piled a lot into the netmf but it does seem like Windows 10 on the RPi is getting the love at the moment. 

The netduino hardware is stable, and the TinyCLR is fairly robust. You're uptime will more depend on the code youre writing that runs on the netduino. Certainly code i've found out the hard way can lock the device requiring a power cycle. If you need continuous running, look more into fault tolerance and recovery than pure uptime. 

Yep, have also ran into that annoying problem. Adding that enum in manually seems to be the only fix available. 

I'm assuming it's a new(-ish) compiler added attribute that's not in the base netmf core lib.

Following up on this, it would appear that COM2 TX is working, as the device i'm connecting to on COM2 is responding to commands sent, but I'm not receiving confirmations back. 
Same code, device swapped to COM1 and it works as expected. COM3 & COM4 also work as expected. 

Dud board? Software Bug?

Both D2 & D3 work successfully with OneWire devices... 

I'm having the same issue with an app i'm porting from the n2plus to the n3. COM1 works as expected, but COM2 is unresponsive. Both working perfectly on the n2plus. Connected on D2 (RX -- TX on external device), D3 (TX -- RX on external device). 

new SerialPort("COM2", 115200, Parity.None, 8, StopBits.One);