diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 1.0.0.1
+
+  * Bump C sources to 1.5.3
+
 # 1.0.0.0
 
   * `compressFile` now takes block size
diff --git a/bz3.cabal b/bz3.cabal
--- a/bz3.cabal
+++ b/bz3.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.4
 name:               bz3
-version:            1.0.0.0
+version:            1.0.0.1
 synopsis:           High-level bindings to bz3
 description:
     Streaming compression/decompression in bz3 format via lazy bytestrings
diff --git a/c/libbz3.c b/c/libbz3.c
--- a/c/libbz3.c
+++ b/c/libbz3.c
@@ -874,7 +874,7 @@
 /* High level API implementations. */
 
 BZIP3_API int bz3_compress(u32 block_size, const u8 * const in, u8 * out, size_t in_size, size_t * out_size) {
-    if (block_size > in_size) block_size = in_size + 16;
+    if (block_size > in_size) block_size = bz3_bound(in_size);
     block_size = block_size <= KiB(65) ? KiB(65) : block_size;
 
     struct bz3_state * state = bz3_new(block_size);
@@ -991,6 +991,8 @@
     }
 
     bz3_free(state);
+    free(compression_buf);
+
     return BZ3_OK;
 }
 
diff --git a/src/Codec/Bz3/Binary.hs b/src/Codec/Bz3/Binary.hs
--- a/src/Codec/Bz3/Binary.hs
+++ b/src/Codec/Bz3/Binary.hs
@@ -3,7 +3,6 @@
 -- https://github.com/kspalaiologos/bzip3/blob/master/doc/bzip3_format.md
 module Codec.Bz3.Binary ( Chunk (..)
                         , getFileH
-                        , getFrameH
                         , getChunk
                         , putFileH
                         , putChunk
@@ -24,10 +23,8 @@
     putWord32le maxSz
 
 -- max block sz
-getFileH, getFrameH :: Get Word32
+getFileH :: Get Word32
 getFileH = do {sig <- getByteString 5; unless (sig=="BZ3v1") $ fail "bad signature"; getWord32le}
-
-getFrameH = getFileH <* getWord32le
 
 putChunk :: Chunk -> Put
 putChunk (Chunk csz osz) = putWord32le csz *> putWord32le osz