diff --git a/resources/definitions/anycubic_i3_mega_s.def.json b/resources/definitions/anycubic_i3_mega_s.def.json
index e1e6fc9dae..d735176df5 100644
--- a/resources/definitions/anycubic_i3_mega_s.def.json
+++ b/resources/definitions/anycubic_i3_mega_s.def.json
@@ -67,8 +67,8 @@
         "speed_topbottom": { "value": "speed_print / 2" },
         "speed_roofing": { "value": "speed_topbottom" },
         "speed_travel": { "value": 100.0,  "maximum_value_warning": 150.0 },
-        "speed_layer_0": { "value": 20.0 },
-        "speed_print_layer_0": { "value": "speed_layer_0" },
+        "speed_layer_0": { "value": "speed_topbottom if speed_topbottom < 20 else 20" },
+        "speed_print_layer_0": { "value": "speed_topbottom if speed_topbottom < 20 else 20" },
         "speed_travel_layer_0": { "value": 100.0 },
         "speed_prime_tower": { "value": "speed_topbottom" },
         "speed_support": { "value": "speed_wall_0" },