diff --git a/python/cclassy.pxd b/python/cclassy.pxd
index 8cc9086e..945a165e 100644
--- a/python/cclassy.pxd
+++ b/python/cclassy.pxd
@@ -60,6 +60,12 @@ cdef extern from "class.h":
         double w0_fld
         double wa_fld
         double cs2_fld
+        short shooting_failed
+        int parameters_size_smg
+        int parameters_2_size_smg
+        double * parameters_smg
+        double * parameters_2_smg
+        int tuning_index_smg
         double Omega0_ur
         double Omega0_dcdmdr
         double Omega0_scf
diff --git a/python/classy.pyx b/python/classy.pyx
index 8e57a5f3..6438840b 100644
--- a/python/classy.pyx
+++ b/python/classy.pyx
@@ -1721,11 +1721,35 @@ cdef class Class:
                 value = self.sp.sigma8
             elif name == 'sigma8_cb':
                 value = self.sp.sigma8_cb
+            elif name == 'Omega0_smg' or name == 'Omega_smg':
+                value = self.Omega0_smg()
+            elif 'parameters_smg_real' in name:
+                value = self.__MontePython_ask_for_array_component(name, self.ba.parameters_smg, self.ba.parameters_size_smg)
+            elif 'parameters_2_smg_real' in name:
+                value = self.__MontePython_ask_for_array_component(name, self.ba.parameters_2_smg, self.ba.parameters_2_size_smg)
+            elif name == 'tuning_parameter':
+                value = self.ba.parameters_smg[self.ba.tuning_index_smg]
             else:
                 raise CosmoSevereError("%s was not recognized as a derived parameter" % name)
             derived[name] = value
         return derived
 
+    cdef __MontePython_ask_for_array_component(self, name, double * carray, carray_size):
+
+        try:
+            index = int(name.split('_')[-1])
+        except:
+            print "Index not given or not an interger: printing the whole array"
+            array = []
+            for i in range(carray_size):
+                array.append(carray[i])
+            return array
+
+        if index <= carray_size:
+            return carray[index-1]
+        else:
+            raise CosmoSevereError("%s index is greater than array length" % name)
+        
     def nonlinear_scale(self, np.ndarray[DTYPE_t,ndim=1] z, int z_size):
         """
         nonlinear_scale(z, z_size)
diff --git a/source/background.c b/source/background.c
index 465e1478..6c68e5d3 100755
--- a/source/background.c
+++ b/source/background.c
@@ -674,7 +674,7 @@ int background_init(
   /** - if shooting failed during input, catch the error here */
   class_test_except(pba->shooting_failed == _TRUE_,
              pba->error_message,
-             background_free(pba),
+             background_free_input(pba),
              "Shooting failed, try optimising input_get_guess(). Error message:\n\n%s",
              pba->shooting_error);
 
@@ -1781,7 +1781,7 @@ int background_solve(
 
     class_test_except((tau_end-tau_start)/tau_start < ppr->smallest_allowed_variation,
                pba->error_message,
-               gt_free(&gTable);cleanup_generic_integrator(&gi);background_free(pba);free(pvecback_integration);free(pvecback),
+               gt_free(&gTable);cleanup_generic_integrator(&gi);background_free_input(pba);free(pvecback_integration);free(pvecback),
                "integration step: relative change in time =%e < machine precision : leads either to numerical error or infinite loop",(tau_end-tau_start)/tau_start);
 
     /* -> save data in growTable */