Unable to open UART port on Windows IoT with Raspberry Pi 3

Question

I have null in the serial port after I open the SerialDevice in C# on Windows IoT Core 10 running on Raspberry Pi 3.

Here is the code:

string aqs = SerialDevice.GetDeviceSelector();
DeviceInformationCollection devices = await DeviceInformation.FindAllAsync(aqs);
List<DeviceInformation> list = devices.ToList();
DeviceInformation di = list.First();
serialPort = await SerialDevice.FromIdAsync(di.Id);

serialPort is null.

di.Id equals: Id "\\\\?\\ACPI#BCM2836#0#{86e0d1e0-8089-11d0-9ce4-08003e301f73}" string

list.Count equal 1

Here are two records from /api/devicemanager/devices GET request related to UART:

{
  "Class": "Ports",
  "Description": "BCM283x Mini UART Serial Device",
  "ID": "ACPI\\BCM2836\\0",
  "Manufacturer": "Microsoft",
  "ParentID": "ACPI_HAL\\PNP0C08\\0",
  "ProblemCode": 0,
  "StatusCode": 25182218
},
{
  "Class": "System",
  "Description": "ARM PL011 UART Device Driver",
  "ID": "ACPI\\BCM2837\\4",
  "Manufacturer": "Microsoft",
  "ParentID": "ACPI_HAL\\PNP0C08\\0",
  "ProblemCode": 0,
  "StatusCode": 25165834
},

I tried both to short circuit Rx and Tx and to not shortly circuit it, it doesn't works...

UPDATE

If I split the given ID, I have Invalid data exception.

string aqs = SerialDevice.GetDeviceSelector();
DeviceInformationCollection devices = await DeviceInformation.FindAllAsync(aqs);
List<DeviceInformation> list = devices.ToList();
DeviceInformation di = list.First();

string id = "{86e0d1e0-8089-11d0-9ce4-08003e301f73}";
try { serialPort = await SerialDevice.FromIdAsync(id); } catch(Exception e) { Debug.WriteLine(e.Message); }
id = "\\\\?\\ACPI#BCM2836#0#";
try { serialPort = await SerialDevice.FromIdAsync(id); } catch(Exception e) { Debug.WriteLine(e.Message); }
id = di.Id;
try { serialPort = await SerialDevice.FromIdAsync(id); } catch(Exception e) { Debug.WriteLine(e.Message); }
if (serialPort == null) { Debug.WriteLine("No device"); return; }

The output:

Exception thrown: 'System.Exception' in mscorlib.ni.dll
The data is invalid. (Exception from HRESULT: 0x8007000D)
The data is invalid. (Exception from HRESULT: 0x8007000D)
No device

Answer 1

As Grim said, the solution is here: SerialDevice.FromIdAsync() yields a null serial port

It is necessary to add:

<DeviceCapability Name="serialcommunication">
  <Device Id="any">
    <Function Type="name:serialPort" />
  </Device>
</DeviceCapability>

in the <Capabilities> tag in Package.appxmanifest file.