diff --git a/src/imb.zig b/src/imb.zig
index ef400dc..0574ae0 100644
--- a/src/imb.zig
+++ b/src/imb.zig
@@ -156,7 +156,7 @@ fn generateChecksum(data: [13]u8) u16 {
     const generator_polynomial: u16 = 0x0F35;
     var checksum: u16 = 0x07ff;
 
-    var byte: u16 = data[0] << 5;
+    var byte: u16 = @as(u16, data[0]) << 5;
 
     for (2..8) |_| {
         if (((checksum ^ byte) & 0x400) != 0) {
@@ -207,7 +207,6 @@ fn decode(bars: [65]BarType) Error!BarcodeResult {
             8, 11 => {
                 character.* ^= 0b1111111111111;
                 checksum |= (@as(u11, 1) << @intCast(i));
-                checksum |= (@as(u11, 1) << @intCast(i));
             },
             2, 5 => {},
             else => return error.DecodingError,
diff --git a/web/imb.wasm b/web/imb.wasm
index b36e8c3..c34d468 100755
Binary files a/web/imb.wasm and b/web/imb.wasm differ