diff --git a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/ElementDeclarationContext.kt b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/ElementDeclarationContext.kt
index 69f1d34f..8d73b2bb 100644
--- a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/ElementDeclarationContext.kt
+++ b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/ElementDeclarationContext.kt
@@ -17,3 +17,7 @@ val ElementDeclarationContext.elementAnnotations: List<Annotation>
 inline fun <reified T : Annotation> ElementDeclarationContext.findElementAnnotation(): T? {
     return elementAnnotations.findAnnotation()
 }
+
+inline fun <reified T : Annotation> ElementDeclarationContext.hasAnnotation(): Boolean {
+    return findElementAnnotation<T>() != null
+}
diff --git a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/annotations/DisableOptionalBooleanOptimization.kt b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/annotations/DisableOptionalBooleanOptimization.kt
new file mode 100644
index 00000000..a653d200
--- /dev/null
+++ b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/annotations/DisableOptionalBooleanOptimization.kt
@@ -0,0 +1,15 @@
+@file:OptIn(ExperimentalSerializationApi::class)
+
+package io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.annotations
+
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.SerialInfo
+
+/**
+ * Disables the SCALE `Option<bool>` single-byte optimization for the annotated `Boolean?` property.
+ * When present, the property is encoded using the standard 2-byte optional encoding:
+ * `0x00` for null, `0x01 0x00` for false, `0x01 0x01` for true.
+ */
+@SerialInfo
+@Target(AnnotationTarget.PROPERTY)
+annotation class DisableOptionalBooleanOptimization
diff --git a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/decoder/BaseCompositeBinaryDecoder.kt b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/decoder/BaseCompositeBinaryDecoder.kt
index a4984809..1493f83b 100644
--- a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/decoder/BaseCompositeBinaryDecoder.kt
+++ b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/decoder/BaseCompositeBinaryDecoder.kt
@@ -2,7 +2,9 @@ package io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.dec
 
 import io.emeraldpay.polkaj.scale.ScaleCodecReader
 import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.ElementDeclarationContext
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.annotations.DisableOptionalBooleanOptimization
 import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.common.ScaleOptional.NULL_MARK
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.findElementAnnotation
 import kotlinx.serialization.DeserializationStrategy
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.descriptors.SerialDescriptor
@@ -70,7 +72,9 @@ abstract class BaseCompositeBinaryDecoder(
         if (nullabilityByte == NULL_MARK) return null
 
         val elementContext = ElementDeclarationContext(index, descriptor)
-        val delegate = PrimitiveBinaryScaleDecoder(serializersModule, reader, elementContext, nullabilityByte)
+        val disableOptBool = elementContext.findElementAnnotation<DisableOptionalBooleanOptimization>() != null
+        val passedNullabilityByte = if (disableOptBool) null else nullabilityByte
+        val delegate = PrimitiveBinaryScaleDecoder(serializersModule, reader, elementContext, passedNullabilityByte)
         return delegate.decodeSerializableValue(deserializer)
     }
 
diff --git a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/encoder/CompositeBinaryEncoder.kt b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/encoder/CompositeBinaryEncoder.kt
index 14992c26..515a970f 100644
--- a/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/encoder/CompositeBinaryEncoder.kt
+++ b/koltinx-serialization-scale/src/main/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/binary/encoder/CompositeBinaryEncoder.kt
@@ -3,9 +3,12 @@ package io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.enc
 import io.emeraldpay.polkaj.scale.ScaleCodecWriter
 import io.novasama.substrate_sdk_android.extensions.toSignedBytes
 import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.ElementDeclarationContext
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.annotations.DisableOptionalBooleanOptimization
 import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.common.ScaleOptional.NOT_NULL_MARK
 import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.common.ScaleOptional.NULL_MARK
 import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.common.encodeOptionalBoolean
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.findElementAnnotation
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.hasAnnotation
 import io.novasama.substrate_sdk_android.scale.utils.directWrite
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.SerializationException
@@ -130,7 +133,7 @@ internal class CompositeBinaryEncoder(
     ) {
         when {
             serializer.descriptor.kind == PrimitiveKind.BOOLEAN -> {
-                writer.encodeOptionalBoolean(value as Boolean?)
+                encodeOptionalBoolean(descriptor, index, value)
             }
 
             value == null -> {
@@ -144,6 +147,26 @@ internal class CompositeBinaryEncoder(
         }
     }
 
+    private fun <T> encodeOptionalBoolean(
+        descriptor: SerialDescriptor,
+        index: Int,
+        value: T?
+    ) {
+        val elementContext = ElementDeclarationContext(index, descriptor)
+        val optimizeBool = !elementContext.hasAnnotation<DisableOptionalBooleanOptimization>()
+
+        when {
+            optimizeBool -> writer.encodeOptionalBoolean(value as Boolean?)
+
+            value == null -> writer.writeByte(NULL_MARK)
+
+            else -> {
+                writer.writeByte(NOT_NULL_MARK)
+                ScaleCodecWriter.BOOL.write(writer, value as Boolean)
+            }
+        }
+    }
+
     private fun unsupported(label: String): Nothing {
         throw SerializationException("Encoding of $label is not supported")
     }
diff --git a/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/decode/binary/OptionalBinaryDecodeTest.kt b/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/decode/binary/OptionalBinaryDecodeTest.kt
index 8afebd09..046a63fe 100644
--- a/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/decode/binary/OptionalBinaryDecodeTest.kt
+++ b/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/decode/binary/OptionalBinaryDecodeTest.kt
@@ -1,5 +1,6 @@
 package io.novasama.substrate_sdk_android.koltinx_serialization_scale.decode.binary
 
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.annotations.DisableOptionalBooleanOptimization
 import kotlinx.serialization.Serializable
 import org.junit.Test
 
@@ -36,4 +37,14 @@ class OptionalBinaryDecodeTest : BinaryDecodeTest() {
         runDecodeTest<TestData>(raw = byteArrayOf(0x01), expected = TestData(false))
         runDecodeTest<TestData>(raw = byteArrayOf(0x02), expected = TestData(true))
     }
+
+    @Test
+    fun `should decode optional boolean without optimization when annotated`() {
+        @Serializable
+        data class TestData(@DisableOptionalBooleanOptimization val a: Boolean?)
+
+        runDecodeTest<TestData>(raw = byteArrayOf(0x00), expected = TestData(null))
+        runDecodeTest<TestData>(raw = byteArrayOf(0x01, 0x00), expected = TestData(false))
+        runDecodeTest<TestData>(raw = byteArrayOf(0x01, 0x01), expected = TestData(true))
+    }
 }
\ No newline at end of file
diff --git a/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/encode/binary/OptionalBinaryEncodeTest.kt b/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/encode/binary/OptionalBinaryEncodeTest.kt
index 8b98a65a..b45b7324 100644
--- a/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/encode/binary/OptionalBinaryEncodeTest.kt
+++ b/koltinx-serialization-scale/src/test/java/io/novasama/substrate_sdk_android/koltinx_serialization_scale/encode/binary/OptionalBinaryEncodeTest.kt
@@ -1,5 +1,6 @@
 package io.novasama.substrate_sdk_android.koltinx_serialization_scale.encode.binary
 
+import io.novasama.substrate_sdk_android.koltinx_serialization_scale.binary.annotations.DisableOptionalBooleanOptimization
 import kotlinx.serialization.Serializable
 import org.junit.Test
 
@@ -32,8 +33,18 @@ class OptionalBinaryEncodeTest : BinaryEncodeTest() {
         @Serializable
         data class TestData(val a: Boolean?)
 
-//        runEncodeTest<TestData>(value = TestData(null), expected = byteArrayOf(0x00))
+        runEncodeTest<TestData>(value = TestData(null), expected = byteArrayOf(0x00))
         runEncodeTest<TestData>(value = TestData(false), expected = byteArrayOf(0x01))
-//        runEncodeTest<TestData>(value = TestData(true), expected = byteArrayOf(0x02))
+        runEncodeTest<TestData>(value = TestData(true), expected = byteArrayOf(0x02))
+    }
+
+    @Test
+    fun `should encode optional boolean without optimization when annotated`() {
+        @Serializable
+        data class TestData(@DisableOptionalBooleanOptimization val a: Boolean?)
+
+        runEncodeTest<TestData>(value = TestData(null), expected = byteArrayOf(0x00))
+        runEncodeTest<TestData>(value = TestData(false), expected = byteArrayOf(0x01, 0x00))
+        runEncodeTest<TestData>(value = TestData(true), expected = byteArrayOf(0x01, 0x01))
     }
 }
\ No newline at end of file