diff --git a/Faust.md b/Faust.md
index c96b039..50d1602 100644
--- a/Faust.md
+++ b/Faust.md
@@ -4,10 +4,20 @@ The [Faust audio DSP language](https://faust.grame.fr) can be used in VCV Protot
 
 ## Compiling on OSX
 
-The Faust *libfaust* library will have to be compiled as a dynamic version, and installed on your machine. Then the [Faust aware VCV Prototype](https://github.com/sletz/VCV-Prototype) can be compiled and installed.
+The Faust *libfaust* dynamic library has to be available in your system. You can get is from a precompiled Faust release (simpler), or compile it yourself (harder). Then the [Faust aware VCV Prototype](https://github.com/sletz/VCV-Prototype) can be compiled and installed.
+
+### Installing the *libfaust* dynamic library from a precompiled package:
+
+- go on Faust [release page](https://github.com/grame-cncm/faust/releases) and get the latest .dmg for OSX.
+- mount the disk image and copy the 3 *libfaust.dylib*, *libfaust.2.dylib* and *libfaust.x.y.z.dylib* files located in the disk image */lib* folder in your system */usr/local/lib* folder
+
+### Compiling the *libfaust* dynamic library:
 
 - clone the [Faust GitHub project](https://github.com/grame-cncm/faust)
 - assuming you have installed the LLVM dependency (with brew or macports on OSX), type `make world` to compile the libfaust libray in dynamic mode (read https://github.com/grame-cncm/faust/wiki/Building if needed)
+
+### Compiling the VCV Prototype:
+
 - clone the [Faust aware VCV Prototype](https://github.com/sletz/VCV-Prototype)  then type `make && make install` to build it
 - you can now add a Faust aware VCV Prototype in your Rack session and start coding in Faust.
 
diff --git a/Makefile b/Makefile
index 69ece5d..db3d1c6 100644
--- a/Makefile
+++ b/Makefile
@@ -263,3 +263,4 @@ FAUST_MAKE_FLAGS += prefix="$(DEP_PATH)"
 endif
 
 include $(RACK_DIR)/plugin.mk
+
diff --git a/src/FaustEngine.cpp b/src/FaustEngine.cpp
index 6de8ad6..504e3ac 100644
--- a/src/FaustEngine.cpp
+++ b/src/FaustEngine.cpp
@@ -79,7 +79,13 @@ struct RackUI : public GenericUI
     {
         int index = getIndex(fValue);
         if (fKey == "switch" && (index != -1)) {
-            fUpdateFunIn.push_back([=] (ProcessBlock* block) { *zone = block->switches[index-1]; });
+            fUpdateFunIn.push_back([=] (ProcessBlock* block)
+            {
+                *zone = block->switches[index-1];
+                
+                // And set the color to red when on
+                block->switchLights[index-1][0] = *zone;
+            });
         }
     }
     
@@ -162,6 +168,11 @@ struct RackUI : public GenericUI
     {
         addBarGraph(zone);
     }
+    
+    void addSoundfile(const char* label, const char* soundpath, Soundfile** sf_zone)
+    {
+        WARN("Faust Prototype : 'soundfile' primitive not yet supported");
+    }
         
     void declare(FAUSTFLOAT* zone, const char* key, const char* val)
     {