diff --git a/sim/transport/gconfig/g4Config.C b/sim/transport/gconfig/g4Config.C
index 96692f783d27ed89859a7dda9a27afc305b19ede..aad1a727f00ff0b26656f26e871b321174ff88f5 100644
--- a/sim/transport/gconfig/g4Config.C
+++ b/sim/transport/gconfig/g4Config.C
@@ -61,11 +61,17 @@ void Config()
   if (cut == 0) gInterpreter->ProcessLine("SetCuts()");
 
 
-  //set geant4 specific stuff
+  // --- Random seed and maximum number of steps
+  size_t buf_size = 100;
+  Text_t buffer[buf_size];
   // Get the infomation about the seed value defined by SetSeed from the base class.
-  // Since ROOT 6.24 the derived classes return a differnt value.
-  Text_t buffer[50];
-  sprintf(buffer, "/random/setSeeds %i  %i ", gRandom->TRandom::GetSeed(), gRandom->TRandom::GetSeed());
+  // Since ROOT 6.24 the derrived classes return a differnt value.
+  Int_t randomSeed = gRandom->TRandom::GetSeed();
+  LOG(info) << "Set Geant4 random seed to " << randomSeed;
+  int result_length = snprintf(buffer, buf_size - 1, "/random/setSeeds %i  %i ", randomSeed, randomSeed);
+  if (!(result_length > 0 && result_length < static_cast<int>(buf_size))) {
+    LOG(fatal) << "Buffer overrun. Random seed for Geant4 would be improper.";
+  }
   geant4->ProcessGeantCommand(buffer);
 
   geant4->SetMaxNStep(10000);  // default is 30000
diff --git a/sim/transport/gconfig/g4config.in b/sim/transport/gconfig/g4config.in
index 30cefff1d39567d63ece2868364b6cd6d7b4dc23..088b462e6510dd268ee5ed697fddff94babbf3ac 100644
--- a/sim/transport/gconfig/g4config.in
+++ b/sim/transport/gconfig/g4config.in
@@ -40,8 +40,9 @@
 # (Needed as Cerenkov process does not limit step itself)
 #
 /process/optical/verbose 0
-/process/optical/defaults/cerenkov/setMaxPhotons 20
-/process/optical/defaults/cerenkov/setMaxBetaChange 0.1
-/process/optical/setTrackSecondariesFirst Cerenkov false
-
-
+/process/optical/cerenkov/setMaxPhotons 20
+/process/optical/cerenkov/setMaxBetaChange 0.1
+/process/optical/cerenkov/setTrackSecondariesFirst true
+/process/optical/processActivation Cerenkov true
+/process/optical/processActivation OpAbsorption true
+/process/optical/processActivation OpBoundary true