diff --git a/plugins/CuraEngineBackend/StartSliceJob.py b/plugins/CuraEngineBackend/StartSliceJob.py
index 94f6d3edfa..29a6d8ff30 100644
--- a/plugins/CuraEngineBackend/StartSliceJob.py
+++ b/plugins/CuraEngineBackend/StartSliceJob.py
@@ -107,7 +107,8 @@ class StartSliceJob(Job):
             return False
 
         # if there are no per-object settings we don't need to check the other settings here
-        if stack.getTop() is None or not stack.getTop().getAllKeys():
+        stack_top = stack.getTop()
+        if stack_top is None or not stack_top.getAllKeys():
             return False
 
         for key in stack.getAllKeys():
diff --git a/resources/definitions/fdmprinter.def.json b/resources/definitions/fdmprinter.def.json
index 65ecbc1c91..5f43cb0bfd 100644
--- a/resources/definitions/fdmprinter.def.json
+++ b/resources/definitions/fdmprinter.def.json
@@ -1190,6 +1190,18 @@
                                     "value": "999999 if infill_sparse_density == 100 else math.ceil(round(bottom_thickness / resolveOrValue('layer_height'), 4))",
                                     "limit_to_extruder": "top_bottom_extruder_nr",
                                     "settable_per_mesh": true
+                                },
+                                "initial_bottom_layers":
+                                {
+                                    "label": "Initial Bottom Layers",
+                                    "description": "The number of initial bottom layers, from the build-plate upwards. When calculated by the bottom thickness, this value is rounded to a whole number.",
+                                    "minimum_value": "0",
+                                    "minimum_value_warning": "2",
+                                    "default_value": 6,
+                                    "type": "int",
+                                    "value": "bottom_layers",
+                                    "limit_to_extruder": "top_bottom_extruder_nr",
+                                    "settable_per_mesh": true
                                 }
                             }
                         }
diff --git a/resources/definitions/ultimaker_s5.def.json b/resources/definitions/ultimaker_s5.def.json
index dfa8da5397..7eb37d0614 100644
--- a/resources/definitions/ultimaker_s5.def.json
+++ b/resources/definitions/ultimaker_s5.def.json
@@ -70,8 +70,6 @@
         "extruder_prime_pos_abs": { "default_value": true },
         "machine_start_gcode": { "default_value": "" },
         "machine_end_gcode": { "default_value": "" },
-        "prime_tower_position_x": { "value": "345" },
-        "prime_tower_position_y": { "value": "222.5" },
         "prime_blob_enable": { "enabled": true, "default_value": false },
 
         "speed_travel":