Accessing SET_TIME Permission on Signed application

Question

So basically I'm building an app and one of those features is to be able to sync up the date time with a value from a database.

(The application is signed - and from what I have read, the SET_TIME permission is "signatureOrSystem" locked, therefore we should be able to access it)

I've got the permission required inside of the AndroidManifest.xml

```

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.SET_TIME" />
<uses-permission android:name="android.permission.SET_TIME_ZONE" />
<uses-permission android:name="android.permission.READ_CALENDAR" />
<uses-permission android:name="android.permission.WRITE_CALENDAR" />

```

And I've also got permission request code sorted (I may be using the wrong request method/class)

```

  if (ActivityCompat.CheckSelfPermission(this, Manifest.Permission.SetTime) != Permission.Granted)
  {
    if (ActivityCompat.ShouldShowRequestPermissionRationale(this, Manifest.Permission.SetTime))
      ActivityCompat.RequestPermissions(this, new string[] { Manifest.Permission.SetTime }, 0);
    else
      ActivityCompat.RequestPermissions(this, new string[] { Manifest.Permission.SetTime }, 0);
  }

```

I've also added some code to ensure that the signature is attached to the debugger

```
  var _context = Android.App.Application.Context;
  foreach (Android.Content.PM.Signature signature in _context.PackageManager.GetPackageInfo(_context.PackageName, PackageInfoFlags.Signatures).Signatures)
  {
    using (SHA1Managed sha1 = new SHA1Managed())
    {
      var hash = sha1.ComputeHash(signature.ToByteArray());
      var sb = new StringBuilder(hash.Length * 2);
      foreach (byte b in hash)
      {
        sb.Append(b.ToString("X2"));
      }

      System.Diagnostics.Debug.WriteLine(sb.ToString());
    }
  }
```

However, I don't seem to be given access to the permission.

Which one signature comes up, which is what is expected. However, upon running through my set time button code:

```

  Button _btn = FindViewById<Button>(Resource.Id.btnSetTime);
  _btn.Click += (sender, e) =>
  { 
    DateTime _time = DateTime.Now;
    Calendar c = Calendar.GetInstance(new Java.Util.Locale("it-IT"));
    c.Set(_time.Year, _time.Month, _time.Day, _time.Hour + 1, _time.Minute, _time.Second);

    AlarmManager am = (AlarmManager)this.GetSystemService(AlarmService);
    am.SetTime(c.TimeInMillis);
  };

```

I am getting the error: Java.Lang.SecurityException: 'setTime: Neither user 10517 nor current process has android.permission.SET_TIME.'

I am wondering if anyone knows why this may be happening and any way to fix this? Or if its possible at all?

Android Version: 9.0 SDK Version: 28