diff --git a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionConfiguration.java b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionConfiguration.java
index 93ba9ce78..3857451a1 100644
--- a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionConfiguration.java
+++ b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionConfiguration.java
@@ -1220,8 +1220,10 @@ public Builder metrics(boolean enabled) {
 
         /**
          * Option to whether the driver should interpret MySQL's TINYINT(1) as a BIT type.
-         * When enabled, TINYINT(1) columns (both SIGNED and UNSIGNED) will be treated as
-         * BIT. default to {@code true}.
+         * When enabled, TINYINT(1) columns will be treated as BIT. Defaults to {@code true}.
+         * <p>
+         * Note: Only signed TINYINT(1) columns can be treated as BIT or Boolean.
+         * Ref: https://bugs.mysql.com/bug.php?id=100309
          *
          * @param tinyInt1isBit {@code true} to treat TINYINT(1) as BIT
          * @return this {@link Builder}
diff --git a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionFactoryProvider.java b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionFactoryProvider.java
index bff335123..5905c56ca 100644
--- a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionFactoryProvider.java
+++ b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/MySqlConnectionFactoryProvider.java
@@ -332,8 +332,10 @@ public final class MySqlConnectionFactoryProvider implements ConnectionFactoryPr
 
     /**
      * Option to whether the driver should interpret MySQL's TINYINT(1) as a BIT type.
-     * When enabled, TINYINT(1) columns (both SIGNED and UNSIGNED) will be treated as
-     * BIT. default to {@code true}.
+     * When enabled, TINYINT(1) columns will be treated as BIT. Defaults to {@code true}.
+     * <p>
+     * Note: Only signed TINYINT(1) columns can be treated as BIT or Boolean.
+     * Ref: https://bugs.mysql.com/bug.php?id=100309
      *
      * @since 1.4.0
      */
diff --git a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/BooleanCodec.java b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/BooleanCodec.java
index 0a59265c3..8fb98c273 100644
--- a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/BooleanCodec.java
+++ b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/BooleanCodec.java
@@ -32,6 +32,8 @@
  */
 final class BooleanCodec extends AbstractPrimitiveCodec<Boolean> {
 
+    private static final Integer INTEGER_ONE = Integer.valueOf(1);
+
     static final BooleanCodec INSTANCE = new BooleanCodec();
 
     private BooleanCodec() {
@@ -86,7 +88,7 @@ public MySqlParameter encode(Object value, CodecContext context) {
     public boolean doCanDecode(MySqlReadableMetadata metadata) {
         MySqlType type = metadata.getType();
         return ((type == MySqlType.BIT || type == MySqlType.TINYINT) &&
-        Integer.valueOf(1).equals(metadata.getPrecision())) || type == MySqlType.VARCHAR;
+        INTEGER_ONE.equals(metadata.getPrecision())) || type == MySqlType.VARCHAR;
     }
 
     public Boolean createFromLong(long l) {
diff --git a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/DefaultCodecs.java b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/DefaultCodecs.java
index ba022875a..34f2c67c1 100644
--- a/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/DefaultCodecs.java
+++ b/r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/codec/DefaultCodecs.java
@@ -45,8 +45,6 @@
  */
 final class DefaultCodecs implements Codecs {
 
-    private static final Integer INTEGER_ONE = Integer.valueOf(1);
-
     private static final List<Codec<?>> DEFAULT_CODECS = InternalArrays.asImmutableList(
         ByteCodec.INSTANCE,
         ShortCodec.INSTANCE,
@@ -369,18 +367,22 @@ private static Class<?> chooseClass(final MySqlReadableMetadata metadata, Class<
         return type.isAssignableFrom(javaType) ? javaType : type;
     }
 
-    private static Class<?> getDefaultJavaType(final MySqlReadableMetadata metadata, final CodecContext codecContext) {
-        final MySqlType type = metadata.getType();
-        final Integer precision = metadata.getPrecision();
 
-        if (INTEGER_ONE.equals(precision) && (type == MySqlType.TINYINT || type == MySqlType.TINYINT_UNSIGNED)
-         && codecContext.isTinyInt1isBit()) {
-            return Boolean.class;
+    private static boolean shouldBeTreatedAsBoolean(final @Nullable Integer precision, final MySqlType type,
+                                                    final CodecContext context) {
+        if (precision == null || precision != 1) {
+            return false;
         }
-
         // ref: https://github.com/asyncer-io/r2dbc-mysql/issues/277
         // BIT(1) should be treated as Boolean by default.
-        if (INTEGER_ONE.equals(precision) && type == MySqlType.BIT) {
+        return type == MySqlType.BIT || type == MySqlType.TINYINT && context.isTinyInt1isBit();
+    }
+
+    private static Class<?> getDefaultJavaType(final MySqlReadableMetadata metadata, final CodecContext codecContext) {
+        final MySqlType type = metadata.getType();
+        final Integer precision = metadata.getPrecision();
+
+        if (shouldBeTreatedAsBoolean(precision, type, codecContext)) {
             return Boolean.class;
         }
 
diff --git a/r2dbc-mysql/src/test/java/io/asyncer/r2dbc/mysql/ConnectionIntegrationTest.java b/r2dbc-mysql/src/test/java/io/asyncer/r2dbc/mysql/ConnectionIntegrationTest.java
index fccd38530..4e4fa34ae 100644
--- a/r2dbc-mysql/src/test/java/io/asyncer/r2dbc/mysql/ConnectionIntegrationTest.java
+++ b/r2dbc-mysql/src/test/java/io/asyncer/r2dbc/mysql/ConnectionIntegrationTest.java
@@ -592,6 +592,19 @@ public void tinyInt1isBitTrueTestValue1() {
         );
     }
 
+    @Test
+    public void tinyInt1isBitTrueTestUnsignedTinyInt1isNotBoolean() {
+        complete(connection -> Mono.from(connection.createStatement("CREATE TEMPORARY TABLE `test` (`id` INT NOT NULL PRIMARY KEY, `value` TINYINT(1) UNSIGNED)").execute())
+                                   .flatMap(IntegrationTestSupport::extractRowsUpdated)
+                                   .thenMany(connection.createStatement("INSERT INTO `test` VALUES (1, 1)").execute())
+                                   .flatMap(IntegrationTestSupport::extractRowsUpdated)
+                                   .thenMany(connection.createStatement("SELECT `value` FROM `test`").execute())
+                                   .flatMap(result -> result.map((row, metadata) -> row.get("value", Object.class)))
+                                   .doOnNext(value -> assertThat(value).isInstanceOf(Short.class))
+                                   .doOnNext(value -> assertThat(value).isEqualTo(Short.valueOf((short)1)))
+        );
+    }
+
     @Test
     public void tinyInt1isBitTrueTestValue0() {
         complete(connection -> Mono.from(connection.createStatement("CREATE TEMPORARY TABLE `test` (`id` INT NOT NULL PRIMARY KEY, `value` TINYINT(1))").execute())