diff --git a/lib/GHCup/Download.hs b/lib/GHCup/Download.hs
index 3792e2a..f0a7425 100644
--- a/lib/GHCup/Download.hs
+++ b/lib/GHCup/Download.hs
@@ -368,7 +368,7 @@ download uri eDigest dest mfn etags
 
                           -- this nonsense is necessary, because some older versions of curl would overwrite
                           -- the destination file when 304 is returned
-                          case fmap T.words . listToMaybe . fmap T.strip . T.lines $ headers of
+                          case fmap T.words . listToMaybe . fmap T.strip . T.lines . getLastHeader $ headers of
                             Just (http':sc:_)
                               | sc == "304"
                               , T.pack "HTTP" `T.isPrefixOf` http' -> $logDebug [i|Status code was 304, not overwriting|]
@@ -447,7 +447,7 @@ download uri eDigest dest mfn etags
 
   parseEtags :: (MonadLogger m, MonadIO m, MonadThrow m) => T.Text -> m (Maybe T.Text)
   parseEtags stderr = do
-    let mEtag = find (\line -> T.pack "etag:" `T.isPrefixOf` T.toLower line) . fmap T.strip . T.lines $ stderr
+    let mEtag = find (\line -> T.pack "etag:" `T.isPrefixOf` T.toLower line) . fmap T.strip . T.lines . getLastHeader $ stderr
     case T.words <$> mEtag of
       (Just []) -> do
         $logDebug "Couldn't parse etags, no input: "
@@ -585,7 +585,21 @@ getWgetOpts =
     Nothing -> pure []
 
 
+-- | Get the url base name.
+--
+-- >>> urlBaseName "/foo/bar/baz"
+-- "baz"
 urlBaseName :: ByteString  -- ^ the url path (without scheme and host)
             -> ByteString
 urlBaseName = snd . B.breakEnd (== _slash) . urlDecode False
 
+
+-- | Curl saves all intermediate connect headers as well, not just the last one, so we make an effort to take the
+-- last HTTP block only. Passing '--suppress-connect-headers' would be better, but it isn't supported by all versions,
+-- also see:
+--   https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/213
+--
+-- >>> getLastHeader "\n\nHTTP/1.0 200 Connection established\n\nHTTP/1.1 304 Not Modified\n"
+-- "HTTP/1.1 304 Not Modified\n"
+getLastHeader :: T.Text -> T.Text
+getLastHeader = T.unlines . lastDef [] . filter (\x -> not (null x)) . splitOn [""] . fmap T.stripEnd . T.lines
diff --git a/lib/GHCup/Utils/Prelude.hs b/lib/GHCup/Utils/Prelude.hs
index f9e5632..f68e9c9 100644
--- a/lib/GHCup/Utils/Prelude.hs
+++ b/lib/GHCup/Utils/Prelude.hs
@@ -68,6 +68,14 @@ import qualified System.Win32.File             as Win32
 #endif
 
 
+-- $setup
+-- >>> import Data.ByteString.Internal (c2w, w2c)
+-- >>> import Test.QuickCheck
+-- >>> import Data.Word8
+-- >>> import Data.Word8
+-- >>> import qualified Data.Text as T
+-- >>> instance Arbitrary T.Text where arbitrary = T.pack <$> arbitrary
+
 
 fS :: IsString a => String -> a
 fS = fromString
@@ -489,7 +497,14 @@ recover action =
 #endif
 
 
--- Gathering monoidal values
+-- | Gathering monoidal values
+--
+-- >>> traverseFold (pure . (:["0"])) ["1","2"]
+-- ["1","0","2","0"]
+-- >>> traverseFold Just ["1","2","3","4","5"]
+-- Just "12345"
+--
+-- prop> \t -> traverseFold Just t === Just (mconcat t)
 traverseFold :: (Foldable t, Applicative m, Monoid b) => (a -> m b) -> t a -> m b
 traverseFold f = foldl (\mb a -> (<>) <$> mb <*> f a) (pure mempty)
 
@@ -499,6 +514,16 @@ forFold = \t -> (`traverseFold` t)
 
 
 -- | Strip @\\r@ and @\\n@ from 'ByteString's
+--
+-- >>> stripNewline "foo\n\n\n"
+-- "foo"
+-- >>> stripNewline "foo\r"
+-- "foo"
+-- >>> stripNewline "foo"
+-- "foo"
+--
+-- prop> \t -> stripNewline (t <> "\n") === stripNewline t
+-- prop> \t -> not (any (isNewLine . c2w) t) ==> stripNewline t == t
 stripNewline :: String -> String
 stripNewline s
   | null s               = []
@@ -507,6 +532,16 @@ stripNewline s
 
 
 -- | Strip @\\r@ and @\\n@ from 'ByteString's
+--
+-- >>> stripNewline' "foo\n\n\n"
+-- "foo"
+-- >>> stripNewline' "foo\r"
+-- "foo"
+-- >>> stripNewline' "foo"
+-- "foo"
+--
+-- prop> \t -> stripNewline' (t <> "\n") === stripNewline' t
+-- prop> \t -> not (T.any (isNewLine . c2w) t) ==> stripNewline' t == t
 stripNewline' :: T.Text -> T.Text
 stripNewline' s
   | T.null s               = mempty
@@ -514,6 +549,14 @@ stripNewline' s
   | otherwise              = T.singleton (T.head s) <> stripNewline' (T.tail s)
 
 
+-- | Is the word8 a newline?
+--
+-- >>> isNewLine (c2w '\n')
+-- True
+-- >>> isNewLine (c2w '\r')
+-- True
+--
+-- prop> \w -> w /= _lf && w /= _cr ==> not (isNewLine w)
 isNewLine :: Word8 -> Bool
 isNewLine w
   | w == _lf = True
@@ -523,8 +566,10 @@ isNewLine w
 
 -- | Split on a PVP suffix.
 --
--- >>> splitOnPVP "-" "ghc-iserv-dyn-9.3.20210706" == ("ghc-iserv-dyn", "9.3.20210706")
--- >>> splitOnPVP "-" "ghc-iserv-dyn"              == ("ghc-iserv-dyn", "")
+-- >>> splitOnPVP "-" "ghc-iserv-dyn-9.3.20210706"
+-- ("ghc-iserv-dyn","9.3.20210706")
+-- >>> splitOnPVP "-" "ghc-iserv-dyn"
+-- ("ghc-iserv-dyn","")
 splitOnPVP :: String -> String -> (String, String)
 splitOnPVP c s = case Split.splitOn c s of
   []  -> def