diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 ## Upcoming
 
+## 1.0.1
+
+Bug fix:
+
+* Don't error if the `packages` field in `stack.yaml` doesn't exist
+
 ## 1.0.0
 
 Initial release of `hpc-lcov`:
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -11,9 +11,9 @@
 
 ### Stack
 
-1. Run `stack build hpc-lcov`
+1. Run `stack install hpc-lcov`
 1. Run your test(s) with coverage, e.g. `stack test --coverage`
-1. Run `stack exec hpc-lcov`
+1. Run `hpc-lcov`
 1. Upload the generated `lcov.info` file to your coverage service
 
 ### Cabal
diff --git a/exe/Main.hs b/exe/Main.hs
--- a/exe/Main.hs
+++ b/exe/Main.hs
@@ -7,7 +7,8 @@
 import Control.Monad (forM)
 import qualified Data.Aeson as JSON
 import qualified Data.Aeson.Types as JSON
-import Data.HashMap.Lazy (HashMap, (!))
+import Data.HashMap.Lazy (HashMap)
+import qualified Data.HashMap.Lazy as HashMap
 import Data.List (find, isPrefixOf)
 import qualified Data.Map as Map
 import Data.Maybe (fromMaybe)
@@ -168,8 +169,12 @@
 
   stackConfigDir <- Path.parent <$> Path.parseAbsFile stackConfigPath
 
-  packagePaths <- maybe (fail $ "Invalid packages field: " ++ show stackConfig) return $
-    JSON.parseMaybe JSON.parseJSON (stackConfig ! "packages")
+  packagePaths <- case HashMap.lookup "packages" stackConfig of
+    Nothing -> pure ["."]
+    Just packagesField ->
+      case JSON.parseMaybe JSON.parseJSON packagesField of
+        Just packages -> return packages
+        Nothing -> fail $ "Invalid packages field: " ++ show stackConfig
 
   forM packagePaths $ \packagePath -> do
     packageDir <- case packagePath of
diff --git a/hpc-lcov.cabal b/hpc-lcov.cabal
--- a/hpc-lcov.cabal
+++ b/hpc-lcov.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: b79ca55a2aa6f2e6e21c1a0a8b3e7cd5351aa31bcdb45110c89044f6271aa51a
+-- hash: fcb5afe73b641055dbaa90b0e976ead73d6bf55fa27df7c61574f3762fc26ad6
 
 name:           hpc-lcov
-version:        1.0.0
+version:        1.0.1
 synopsis:       Convert HPC output into LCOV format
 description:    Convert HPC output into LCOV format.
 category:       Control
@@ -54,7 +54,7 @@
       exe
   ghc-options: -Wall
   build-depends:
-      aeson >=1.1.2.0 && <1.5
+      aeson >=1.1.2.0 && <1.6
     , base >=4.9 && <5
     , containers >=0.5.7.1 && <0.7
     , hpc >=0.6.0.3 && <0.7
diff --git a/src/Trace/Hpc/Lcov/Report.hs b/src/Trace/Hpc/Lcov/Report.hs
--- a/src/Trace/Hpc/Lcov/Report.hs
+++ b/src/Trace/Hpc/Lcov/Report.hs
@@ -11,9 +11,7 @@
   ) where
 
 import Data.List (intercalate)
-import Data.Word (Word32)
 import Trace.Hpc.Util (Hash)
-import Unsafe.Coerce (unsafeCoerce)
 
 -- http://ltp.sourceforge.net/coverage/lcov/geninfo.1.php
 newtype LcovReport = LcovReport [FileReport]
@@ -70,10 +68,9 @@
     showFunctionHits FunctionReport{..} = line "FNDA" [show functionReportHits, functionReportName]
 
     generateBranchReport BranchReport{..} =
-      let branchHash = unsafeCoerce branchReportHash :: Word32
-          mkBranchLine branchNum hits = line "BRDA"
+      let mkBranchLine branchNum hits = line "BRDA"
             [ show branchReportLine
-            , show branchHash
+            , show branchReportHash
             , show (branchNum :: Int)
             , show hits
             ]