diff --git a/Cabal/ChangeLog.md b/Cabal/ChangeLog.md
index ba4e508ff1f..607fb6aa6c2 100644
--- a/Cabal/ChangeLog.md
+++ b/Cabal/ChangeLog.md
@@ -7,6 +7,8 @@
   * Add `extra-dynamic-library-flavours`, to specify extra dynamic library
     flavours to build and install from a .cabal file.
   * `autoconfUserHooks` now passes `--host=$HOST` when cross-compiling
+  * Fix corrupted config file header for non-ASCII package names
+    ([2557](https://github.com/haskell/cabal/issues/2557)).
 
 ----
 
diff --git a/Cabal/Distribution/Simple/Configure.hs b/Cabal/Distribution/Simple/Configure.hs
index 0b8663e53ae..8fa8eed4b76 100644
--- a/Cabal/Distribution/Simple/Configure.hs
+++ b/Cabal/Distribution/Simple/Configure.hs
@@ -276,7 +276,7 @@ parseHeader header = case BLC8.words header of
   ["Saved", "package", "config", "for", pkgId, "written", "by", cabalId,
    "using", compId] ->
       fromMaybe (throw ConfigStateFileBadHeader) $ do
-          _ <- simpleParsec (BLC8.unpack pkgId) :: Maybe PackageIdentifier
+          _ <- simpleParsec (fromUTF8LBS pkgId) :: Maybe PackageIdentifier
           cabalId' <- simpleParsec (BLC8.unpack cabalId)
           compId' <- simpleParsec (BLC8.unpack compId)
           return (cabalId', compId')
@@ -287,7 +287,7 @@ showHeader :: PackageIdentifier -- ^ The processed package.
             -> ByteString
 showHeader pkgId = BLC8.unwords
     [ "Saved", "package", "config", "for"
-    , BLC8.pack $ prettyShow pkgId
+    , toUTF8LBS $ prettyShow pkgId
     , "written", "by"
     , BLC8.pack $ prettyShow currentCabalId
     , "using"