diff --git a/convert.py b/convert.py
index c29c032cd..635c3e275 100644
--- a/convert.py
+++ b/convert.py
@@ -69,6 +69,9 @@ SAFETENSORS_DATA_TYPES: Dict[str, DataType] = {
     'I32': DT_I32,
 }
 
+# TODO: match this with `llama_ftype`
+# TODO: rename to LLAMAFileType
+# TODO: move to `gguf.py`
 class GGMLFileType(enum.Enum):
     AllF32    = 0
     MostlyF16 = 1  # except 1d tensors
@@ -101,6 +104,8 @@ class Params:
     n_head_kv:  int
     f_norm_eps: float
 
+    ftype: Optional[GGMLFileType] = None
+
     @staticmethod
     def find_n_mult(n_ff: int, n_embd: int) -> int:
         # hardcoded magic range
@@ -738,6 +743,9 @@ class OutputFile:
         self.gguf.add_head_count_kv       (params.n_head_kv)
         self.gguf.add_layer_norm_rms_eps  (params.f_norm_eps)
 
+        if params.ftype:
+            self.gguf.add_file_type(params.ftype)
+
     def add_meta_vocab(self, vocab: Vocab) -> None:
         tokens = []
         scores = []
@@ -1020,6 +1028,12 @@ def main(args_in: Optional[List[str]] = None) -> None:
                             " - LLaMA v2: --ctx 4096\n")
         params.n_ctx = args.ctx
 
+    if args.outtype:
+        params.ftype = {
+            "f32": GGMLFileType.AllF32,
+            "f16": GGMLFileType.MostlyF16,
+        }[args.outtype]
+
     print(f"params = {params}")
 
     vocab: Vocab
@@ -1040,11 +1054,14 @@ def main(args_in: Optional[List[str]] = None) -> None:
             vocab_dir = args.vocab_dir if args.vocab_dir else model_plus.paths[0].parent
             vocab = load_vocab(vocab_dir, args.vocabtype)
 
-        model       = model_plus.model
-        model       = convert_model_names(model, params)
-        output_type = pick_output_type(model, args.outtype)
-        model       = convert_to_output_type(model, output_type)
-        outfile     = args.outfile or default_outfile(model_plus.paths, output_type)
+        model   = model_plus.model
+        model   = convert_model_names(model, params)
+        ftype   = pick_output_type(model, args.outtype)
+        model   = convert_to_output_type(model, ftype)
+        outfile = args.outfile or default_outfile(model_plus.paths, ftype)
+
+        params.ftype = ftype
+        print(f"Writing {outfile}, format {ftype}")
 
         OutputFile.write_all(outfile, params, model, vocab)
         print(f"Wrote {outfile}")
diff --git a/gguf.py b/gguf.py
index 9e71a9d94..465746718 100644
--- a/gguf.py
+++ b/gguf.py
@@ -597,7 +597,7 @@ class GGUFWriter:
         self.add_string(KEY_GENERAL_SOURCE_HF_REPO, repo)
 
     def add_file_type(self, ftype: int):
-        self.add_string(KEY_GENERAL_FILE_TYPE, file_type)
+        self.add_uint32(KEY_GENERAL_FILE_TYPE, ftype)
 
     def add_name(self, name: str):
         self.add_string(KEY_GENERAL_NAME, name)