diff --git a/PKHeX.Core/Saves/Encryption/SwishCrypto/SCTypeCode.cs b/PKHeX.Core/Saves/Encryption/SwishCrypto/SCTypeCode.cs
index 6ab43434c..7f2d12bca 100644
--- a/PKHeX.Core/Saves/Encryption/SwishCrypto/SCTypeCode.cs
+++ b/PKHeX.Core/Saves/Encryption/SwishCrypto/SCTypeCode.cs
@@ -32,7 +32,7 @@ public enum SCTypeCode : byte
 
     public static class SCTypeCodeExtensions
     {
-        public static bool IsBoolean(this SCTypeCode type) => (byte)type - 1 < 3;
+        public static bool IsBoolean(this SCTypeCode type) => unchecked((uint)type - 1) < 3;
 
         public static int GetTypeSize(this SCTypeCode type) => type switch
         {