diff --git a/runtime/src/main/cpp/Arrays.cpp b/runtime/src/main/cpp/Arrays.cpp
index cc2a956ea69..91546c7704b 100644
--- a/runtime/src/main/cpp/Arrays.cpp
+++ b/runtime/src/main/cpp/Arrays.cpp
@@ -467,17 +467,18 @@ KInt Kotlin_NativePtrArray_getArrayLength(KConstRef thiz) {
   return array->count_;
 }
 
-OBJ_GETTER(Kotlin_ImmutableBlob_toByteArray, KConstRef thiz, KInt start, KInt count) {
-   const ArrayHeader* array = thiz->array();
-   if (start < 0 || count < 0 || start > array->count_ - count)  {
-        ThrowArrayIndexOutOfBoundsException();
-    }
-    ArrayHeader* result = AllocArrayInstance(
-          theByteArrayTypeInfo, count, OBJ_RESULT)->array();
-    memcpy(PrimitiveArrayAddressOfElementAt<KByte>(result, 0),
-           PrimitiveArrayAddressOfElementAt<KByte>(array, start),
-           count);
-    RETURN_OBJ(result->obj());
+OBJ_GETTER(Kotlin_ImmutableBlob_toByteArray, KConstRef thiz, KInt startIndex, KInt endIndex) {
+  const ArrayHeader* array = thiz->array();
+  if (startIndex < 0 || endIndex > array->count_ || startIndex > endIndex) {
+      ThrowArrayIndexOutOfBoundsException();
+  }
+  KInt count = endIndex - startIndex;
+  ArrayHeader* result = AllocArrayInstance(
+      theByteArrayTypeInfo, count, OBJ_RESULT)->array();
+  memcpy(PrimitiveArrayAddressOfElementAt<KByte>(result, 0),
+         PrimitiveArrayAddressOfElementAt<KByte>(array, startIndex),
+         count);
+  RETURN_OBJ(result->obj());
 }
 
 KNativePtr Kotlin_ImmutableBlob_asCPointerImpl(KRef thiz, KInt offset) {
diff --git a/runtime/src/main/kotlin/kotlin/native/Blob.kt b/runtime/src/main/kotlin/kotlin/native/Blob.kt
index 84c9fe9ca97..5e02288bc77 100644
--- a/runtime/src/main/kotlin/kotlin/native/Blob.kt
+++ b/runtime/src/main/kotlin/kotlin/native/Blob.kt
@@ -42,19 +42,23 @@ private class ImmutableBlobIteratorImpl(val blob: ImmutableBlob) : ByteIterator(
 }
 
 /**
- * Allocates new [ByteArray] and copies the data from blob starting from [start]
- * and with [count] amount of bytes.
+ * Copies the data from this blob into a new [ByteArray].
+ *
+ * @param startIndex the beginning (inclusive) of the subrange to copy, 0 by default.
+ * @param endIndex the end (exclusive) of the subrange to copy, size of this blob by default.
  */
 @SymbolName("Kotlin_ImmutableBlob_toByteArray")
-public external fun ImmutableBlob.toByteArray(start: Int = 0, count: Int = size): ByteArray
+public external fun ImmutableBlob.toByteArray(startIndex: Int = 0, endIndex: Int = size): ByteArray
 
 /**
- * Allocates new [UByteArray] and copies the data from blob starting from [start]
- * and with [count] amount of bytes.
+ * Copies the data from this blob into a new [UByteArray].
+ *
+ * @param startIndex the beginning (inclusive) of the subrange to copy, 0 by default.
+ * @param endIndex the end (exclusive) of the subrange to copy, size of this blob by default.
  */
 @ExperimentalUnsignedTypes
 @SymbolName("Kotlin_ImmutableBlob_toByteArray")
-public external fun ImmutableBlob.toUByteArray(start: Int = 0, count: Int = size): UByteArray
+public external fun ImmutableBlob.toUByteArray(startIndex: Int = 0, endIndex: Int = size): UByteArray
 
 /**
  * Returns stable C pointer to data at certain [offset], useful as a way to pass resource