diff --git a/c_tools/mock/flash_loader.cpp b/c_tools/mock/flash_loader.cpp
new file mode 100644
index 0000000..50e769f
--- /dev/null
+++ b/c_tools/mock/flash_loader.cpp
@@ -0,0 +1,111 @@
+#include <cassert>
+#include <string>
+#include <CosmoTool/loadFlash.hpp>
+#include <CosmoTool/fortran.hpp>
+#include "simulation_loader.hpp"
+
+using namespace std;
+using namespace CosmoTool;
+
+class FlashLoader: public SimulationLoader
+{
+private:
+  int load_flags;
+  bool onefile;
+  int _num_files;
+  SimuData *gadget_header;
+  string snapshot_name;
+public:
+  FlashLoader(const string& basename, SimuData *header, int flags, bool singleFile, int _num)
+    : snapshot_name(basename), load_flags(flags), onefile(singleFile), _num_files(_num), gadget_header(header)
+  {
+  }
+  
+  ~FlashLoader()
+  {
+    delete gadget_header;
+  }
+  
+  SimuData *getHeader() {
+    return gadget_header;
+  }
+  
+  int num_files() {
+    return _num_files;
+  }
+  
+  SimuData *loadFile(int id) {
+    SimuData *d;
+    
+    if (onefile && id > 0)
+      return 0;
+    if (id >= _num_files)
+      return 0;
+
+    if (onefile)
+      d = loadFlashMulti(snapshot_name.c_str(), -1, load_flags);
+    else
+      d = loadFlashMulti(snapshot_name.c_str(), id, load_flags);
+
+    if (d->Id != 0)
+      {
+	long *uniqueID = new long[d->NumPart];
+	for (long i = 0; i < d->NumPart; i++)
+	  {
+	    uniqueID[i] = d->Id[i];
+	  }
+	d->new_attribute("uniqueID", uniqueID, delete_adaptor<long>);
+      }
+
+    applyTransformations(d);
+
+    return d;
+  }
+};
+
+
+SimulationLoader *flashLoader(const std::string& snapshot, int flags)
+{
+  bool singleFile;
+  int num_files;
+  SimuData *d;
+
+  try
+    {
+      d = loadFlashMulti(snapshot.c_str(), -1, 0);
+      singleFile = true;
+      num_files = 1;
+    }
+  catch (const NoSuchFileException& e)
+    {
+      try
+        {
+          d = loadFlashMulti(snapshot.c_str(), 0, 0);
+	  num_files = 0;
+        }
+      catch(const NoSuchFileException& e)
+        {
+          return 0;
+        }
+    }
+    
+  assert(d != 0);
+  SimuData *header = d;
+    
+  if (!singleFile)
+    {
+      try
+	{
+	  while ((d = loadFlashMulti(snapshot.c_str(), num_files, 0)) != 0)
+	    {
+	      num_files++;
+	      delete d;
+	    }
+	}
+      catch(const NoSuchFileException& e)
+	{
+	}
+    }
+    
+  return new FlashLoader(snapshot, header, flags, singleFile, num_files);
+}
diff --git a/c_tools/mock/generateMock.cpp b/c_tools/mock/generateMock.cpp
index 670fe84..a4a1eb2 100644
--- a/c_tools/mock/generateMock.cpp
+++ b/c_tools/mock/generateMock.cpp
@@ -507,8 +507,7 @@ int main(int argc, char **argv)
     }
   else if (args_info.flash_given)
     {
-      //if (args_info.flash_given) {
-      //simu = doLoadSimulation(args_info.flash_arg, args_info.axis_arg, false, loadFlashMulti); 
+      loader = flashLoader(args_info.flash_arg, NEED_POSITION|NEED_VELOCITY|NEED_GADGET_ID); 
   }
   else if (args_info.multidark_given)
     {