diff --git a/csharp/readme.md b/csharp/readme.md
index 2e301e8c1750..74572b5f1750 100644
--- a/csharp/readme.md
+++ b/csharp/readme.md
@@ -106,7 +106,8 @@ For example, to build a CUDA GPU package, just run:
     /p:TargetFrameworks=netstandard2.0 \
     /p:IsLinuxBuild=true
 ```
-**Note**: build pure cpu development package is not supported at the moment.
+**Note**: to build a pure CPU development package, you need to add `/p:OrtPackageId="Microsoft.ML.OnnxRuntime"`
+to `--msbuild_extra_options`. Otherwise, it will try to create Xamarin mobile targets which may not be properly configured on your devbox.
 
 A `.nupkg` file will be produced at you build root, say, `build/Release`.
 
diff --git a/tools/ci_build/build.py b/tools/ci_build/build.py
index 40180aa8bacc..4c34ebcb0c85 100644
--- a/tools/ci_build/build.py
+++ b/tools/ci_build/build.py
@@ -2035,6 +2035,8 @@ def build_nuget_package(
     elif use_snpe:
         execution_provider = '/p:ExecutionProvider="snpe"'
         package_name = '/p:OrtPackageId="Microsoft.ML.OnnxRuntime.Snpe"'
+    elif any(map(lambda x: "OrtPackageId=" in x, msbuild_extra_options)):
+        pass
     else:
         # use the solution file that includes Xamarin mobile targets
         sln = "OnnxRuntime.CSharp.sln"