I am using Android's extensions for Eclipse and the JUnit framework to benchmark Android applications w.r.t. performance. As I want to compare my apps with built-in Android apps (e.g., Android's built-in browser), I need to resign these apps to be able to instrument them with the JUnit instrumentation runner.

I am able to fetch the apps from the system/app directory from my phone as well as to resign them using the re-sign.jar. However, I am not able to replace the app on my phone with the resigned version.

I tried both 

```
adb install -r Resigned.app

```

and

```
abd uninstall com.android.<originalapp>

```

but both do not work. 

Is the replacement of standard apps even possible? 

Can I replace the apps by overwriting ther apk files under system/app?