diff --git a/MPF.Modules/BaseParameters.cs b/MPF.Modules/BaseParameters.cs
index f2b16168..ae077075 100644
--- a/MPF.Modules/BaseParameters.cs
+++ b/MPF.Modules/BaseParameters.cs
@@ -1857,7 +1857,7 @@ namespace MPF.Modules
                         {
                             case 'S':
                                 // Check first two digits of S_PS serial
-                                switch (serial.Substring(4, 2))
+                                switch (serial.Substring(5, 2))
                                 {
                                     case "46": return Region.SouthKorea;
                                     case "56": return Region.SouthKorea;
@@ -1867,7 +1867,7 @@ namespace MPF.Modules
                                 }
                             case 'M':
                                 // Check first three digits of S_PM serial
-                                switch (serial.Substring(4, 3))
+                                switch (serial.Substring(5, 3))
                                 {
                                     case "645": return Region.SouthKorea;
                                     case "675": return Region.SouthKorea;