diff --git a/gguf-py/gguf/gguf_writer.py b/gguf-py/gguf/gguf_writer.py
index 75fb6976f..c3b8c588f 100644
--- a/gguf-py/gguf/gguf_writer.py
+++ b/gguf-py/gguf/gguf_writer.py
@@ -57,9 +57,9 @@ class GGUFWriter:
         self.endianess = endianess
         self.offset_tensor = 0
         self.data_alignment = GGUF_DEFAULT_ALIGNMENT
-        self.kv_data = b""
+        self.kv_data = bytearray()
         self.kv_data_count = 0
-        self.ti_data = b""
+        self.ti_data = bytearray()
         self.ti_data_count = 0
         self.use_temp_file = use_temp_file
         self.temp_file = None
diff --git a/gguf-py/pyproject.toml b/gguf-py/pyproject.toml
index e21c3cd94..af777c3e0 100644
--- a/gguf-py/pyproject.toml
+++ b/gguf-py/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "gguf"
-version = "0.5.1"
+version = "0.5.2"
 description = "Read and write ML models in GGUF for GGML"
 authors = ["GGML <ggml@ggml.ai>"]
 packages = [