1. Build CoreCLR and note your output directory. Ex: `\coreclr\bin\Product\Windows_NT.x64.Release\` Note this will vary based on your OS/Architecture/Flavor and it is generally a good idea to use Release builds for CoreCLR when running CoreFx tests and the OS and Architecture should match what you are building in CoreFx.
2. Build CoreFx either passing in the `CoreCLROverridePath` property or setting it as an environment variable:
```
-build.cmd -- /p:CoreCLROverridePath=d:\git\coreclr\bin\Product\Windows_NT.x64.Release\
+build.cmd /p:CoreCLROverridePath=d:\git\coreclr\bin\Product\Windows_NT.x64.Release\
```
When we copy the files to override the CoreCLR we do a hard-link copy, so in general if you rebuild CoreCLR the new binaries should be reflected in CoreFx for subsequent builds of individual projects in corefx. However if you want to force refresh or if you want to just update the CoreCLR after you already ran `build.cmd` from CoreFx you can run the following command: