diff --git a/bittide-experiments/src/Bittide/Hitl.hs b/bittide-experiments/src/Bittide/Hitl.hs
index 7f2462239..1e43c8861 100644
--- a/bittide-experiments/src/Bittide/Hitl.hs
+++ b/bittide-experiments/src/Bittide/Hitl.hs
@@ -47,7 +47,6 @@ module Bittide.Hitl (
   -- * Test definition
   HitlTestGroup (..),
   HitlTestCase (..),
-  CasePreProcessing (..),
   TestStepResult (..),
   MayHavePostProcData (..),
   Done,
@@ -189,7 +188,6 @@ and requires a (hypothetical) 8-bit number indicating the
 >           , postProcData = ()
 >           }
 >       ]
->   , mPreProc = Nothing
 >   , mPostProc = Nothing
 >   }
 
@@ -197,18 +195,14 @@ This must be accompanied by a @hitlVio \@NumberOfStages@ in the design.
 -}
 data HitlTestGroup where
   HitlTestGroup ::
-    (Typeable a, Typeable b, Typeable c) =>
+    (Typeable a, Typeable b) =>
     { topEntity :: ClashTargetName
     -- ^ Reference to the Design Under Test
     , extraXdcFiles :: [String]
-    , testCases :: [HitlTestCase HwTargetRef a b c]
+    , testCases :: [HitlTestCase HwTargetRef a b]
     -- ^ List of test cases
-    , mPreProc ::
-        ( VivadoHandle -> String -> FilePath -> HwTarget -> DeviceInfo -> IO (TestStepResult c)
-        )
-    -- ^ Pre-processing step. First argument is the name of the test
     , mDriverProc ::
-        Maybe (VivadoHandle -> String -> FilePath -> [(HwTarget, DeviceInfo, c)] -> IO ExitCode)
+        Maybe (VivadoHandle -> String -> FilePath -> [(HwTarget, DeviceInfo)] -> IO ExitCode)
     -- ^ Optional function driving the test after pre-processing.
     , mPostProc :: Maybe (FilePath -> ExitCode -> IO (TestStepResult ()))
     -- ^ Optional post processing step.
@@ -220,36 +214,25 @@ data HitlTestGroup where
 {- | A HITL test case. One HITL test group can have multiple test cases
 associated with it.
 -}
-data HitlTestCase h a b c where
+
+data HitlTestCase h a b where
   HitlTestCase ::
-    (Show h, Show a, BitPack a, Show b, Typeable h, Typeable c) =>
+    (Show h, Show a, BitPack a, Show b, Typeable h) =>
     { name :: String
     , parameters :: Map h a
-    , preProc :: CasePreProcessing c
     , postProcData :: b
     } ->
-    HitlTestCase h a b c
-
-deriving instance Show (HitlTestCase h a b c)
-
-data CasePreProcessing c
-  = InheritPreProcess
-  | -- | Instead of using the test-group pre-process function, use an override for
-    -- this specific test case.
-    CustomPreProcess
-      (VivadoHandle -> FilePath -> HwTarget -> DeviceInfo -> IO (TestStepResult c))
+    HitlTestCase h a b
 
-instance Show (CasePreProcessing a) where
-  show InheritPreProcess = "InheritPreProcess"
-  show (CustomPreProcess _) = "CustomPreProcess <func>"
+deriving instance Show (HitlTestCase h a b)
 
 -- | A class for extracting optional post processing data from a test.
 class MayHavePostProcData b where
   -- | Returns the test names with some post processing data of type @c@,
   -- if that data exists.
   mGetPPD ::
-    forall h a c.
-    [HitlTestCase h a b c] ->
+    forall h a.
+    [HitlTestCase h a b] ->
     Map String (Maybe b)
 
 instance MayHavePostProcData a where
@@ -292,26 +275,24 @@ to it and receives that constructur as test parameter.
 > testCases = testCasesFromEnum @ABC allHwTargets ()
 -}
 testCasesFromEnum ::
-  forall a b c.
+  -- forall a b c.
+  forall a b.
   ( Show a
   , Bounded a
   , Enum a
   , BitPack a
   , Show b
-  , Show c
   , Typeable a
   , Typeable b
-  , Typeable c
   ) =>
   [HwTargetRef] ->
   b ->
-  [HitlTestCase HwTargetRef a b c]
+  [HitlTestCase HwTargetRef a b]
 testCasesFromEnum hwTs ppd =
   [ HitlTestCase
     { name = show constr
     , parameters = Map.fromList ((,constr) <$> hwTs)
     , postProcData = ppd
-    , preProc = InheritPreProcess
     }
   | (constr :: a) <- [minBound ..]
   ]
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/BoardTest.hs b/bittide-instances/src/Bittide/Instances/Hitl/BoardTest.hs
index 2afe30775..3a45f0db8 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/BoardTest.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/BoardTest.hs
@@ -22,13 +22,11 @@ import Bittide.Instances.Hitl.Post.BoardTestExtended
 import Bittide.Instances.Hitl.Post.PostProcess
 
 import Bittide.Hitl (
-  CasePreProcessing (..),
   HitlTestCase (..),
   HitlTestGroup (..),
   TestStepResult (..),
   hitlVio,
   hitlVioBool,
-  noPreProcess,
   paramForHwTargets,
   testCasesFromEnum,
  )
@@ -189,11 +187,11 @@ testSimple =
             { name = "Simple"
             , parameters = (paramForHwTargets allHwTargets ())
             , postProcData = ()
-            , preProc = InheritPreProcess
+            -- , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = noPreProcess
-    , mDriverProc = Nothing
+    , -- , mPreProc = noPreProcess
+      mDriverProc = Nothing
     , mPostProc = Nothing
     }
 
@@ -204,7 +202,6 @@ testExtended =
     , extraXdcFiles = []
     , externalHdl = []
     , testCases = testCasesFromEnum @Test allHwTargets ()
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Just postBoardTestExtendedFunc
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/DnaOverSerial.hs b/bittide-instances/src/Bittide/Instances/Hitl/DnaOverSerial.hs
index 8f84efd68..78c969a35 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/DnaOverSerial.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/DnaOverSerial.hs
@@ -97,10 +97,8 @@ tests =
             { name = "DnaOverSerial"
             , parameters = paramForHwTargets allHwTargets ()
             , postProcData = ()
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = dnaOverSerialPreProcess
     , mDriverProc = Just dnaOverSerialDriver
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/Driver/DnaOverSerial.hs b/bittide-instances/src/Bittide/Instances/Hitl/Driver/DnaOverSerial.hs
index 99a12feb1..09e03fc52 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/Driver/DnaOverSerial.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/Driver/DnaOverSerial.hs
@@ -16,6 +16,7 @@ import Bittide.Instances.Hitl.Utils.Program
 import Bittide.Instances.Hitl.Utils.Vivado
 import Control.Exception
 import Control.Monad.Extra
+import Data.Either (partitionEithers)
 import qualified Data.List as L
 import Data.Maybe
 import Numeric
@@ -63,14 +64,26 @@ dnaOverSerialDriver ::
   VivadoHandle ->
   String ->
   FilePath ->
-  [(HwTarget, DeviceInfo, (ProcessStdIoHandles, IO ()))] ->
+  [(HwTarget, DeviceInfo)] ->
   IO ExitCode
 dnaOverSerialDriver v _name ilaPath targets = do
-  flip finally (forM targets $ \(_, _, (_, cleanup)) -> cleanup) $ do
+  preProcessResults <- forM targets $ \(hwT, dI) -> do
+    dnaOverSerialPreProcess v _name ilaPath hwT dI >>= \case
+      TestStepSuccess out -> pure $ Right out
+      TestStepFailure reason -> pure $ Left reason
+
+  let (preProcessFails, preProcessPasses) = partitionEithers preProcessResults
+
+  unless (null preProcessFails) $ do
+    let failReason = "some preprocess steps failed. reasons:\n - " <> L.intercalate "\n - " preProcessFails
+    forM_ preProcessPasses snd
+    assertFailure failReason
+
+  flip finally (forM preProcessPasses snd) $ do
     putStrLn "Starting all targets to read DNA values"
 
     -- start all targets
-    forM_ targets $ \(hwT, _, _) -> do
+    forM_ targets $ \(hwT, _) -> do
       openHwT v hwT
       execCmd_ v "set_property" ["PROBES.FILE", embrace ilaPath, "[current_hw_device]"]
       refresh_hw_device v []
@@ -80,16 +93,16 @@ dnaOverSerialDriver v _name ilaPath targets = do
 
     putStrLn "Expecting specific DNAs for all serial ports"
     putStrLn "Serial ports:"
-    mapM_ putStrLn [d.serial | (_, d, _) <- targets]
+    mapM_ putStrLn [d.serial | (_, d) <- targets]
 
-    results <- forM targets $ \(_, d, (picoCom, picoClean)) -> do
+    results <- forM (L.zip targets preProcessPasses) $ \((_, d), (picoCom, picoClean)) -> do
       res <- checkDna d picoCom
       picoClean
-      pure $ res
+      pure res
 
     print results
-    if (and results)
-      then pure $ ExitSuccess
+    if and results
+      then pure ExitSuccess
       else do
         assertFailure "Not all FPGAs transmitted the expected DNA"
         pure $ ExitFailure 2
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscv.hs b/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscv.hs
index 5c7b55438..2171a92d6 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscv.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscv.hs
@@ -27,8 +27,9 @@ import Bittide.Instances.Hitl.Utils.Program
 import Bittide.Instances.Hitl.Utils.Vivado
 
 import Control.Concurrent (threadDelay)
-import Control.Exception (SomeException, catch, displayException)
-import Control.Monad (forM)
+import Control.Exception (SomeException, displayException, handle)
+import Control.Monad (forM, forM_, unless)
+import Data.Either (partitionEithers)
 import qualified Data.List as L
 import Data.Maybe (fromJust, fromMaybe)
 import System.Exit
@@ -36,6 +37,7 @@ import System.FilePath
 import System.IO
 import System.Process
 import System.Timeout (timeout)
+import Test.Tasty.HUnit (assertFailure)
 
 preProcessFunc ::
   VivadoHandle ->
@@ -151,16 +153,24 @@ driverFunc ::
   VivadoHandle ->
   String ->
   FilePath ->
-  [ ( HwTarget
-    , DeviceInfo
-    , ()
-    )
-  ] ->
+  [(HwTarget, DeviceInfo)] ->
   IO ExitCode
 driverFunc v _name ilaPath targets = do
   putStrLn
     $ "Running Driver function for targets "
-    <> show ((\(_, info, _) -> info.deviceId) <$> targets)
+    <> show ((\(_, info) -> info.deviceId) <$> targets)
+
+  preProcessResults <- forM targets $ \(hwT, dI) -> do
+    preProcessFunc v _name ilaPath hwT dI >>= \case
+      TestStepSuccess out -> pure $ Right out
+      TestStepFailure reason -> pure $ Left reason
+
+  let (preProcessFails, preProcessPasses) = partitionEithers preProcessResults
+
+  unless (null preProcessFails) $ do
+    let failReason = "some preprocess steps failed. reasons:\n - " <> L.intercalate "\n - " preProcessFails
+    forM_ preProcessPasses (\(_, _, _, cleanup) -> cleanup)
+    assertFailure failReason
 
   let
     catchError :: DeviceInfo -> SomeException -> IO ExitCode
@@ -168,10 +178,9 @@ driverFunc v _name ilaPath targets = do
       putStrLn $ "Test Failed on device " <> d.deviceId <> " with: " <> displayException ex
       pure $ ExitFailure 2
 
-  exitCodes <- forM targets $ \(hwT, d, ()) -> flip catch (catchError d) $ do
+  exitCodes <- forM (L.zip targets preProcessPasses) $ \((hwT, d), _) -> handle (catchError d) $ do
     putStrLn $ "Running driver for " <> d.deviceId
 
-
     openHwT v hwT
     execCmd_ v "set_property" ["PROBES.FILE", embrace ilaPath, "[current_hw_device]"]
     refresh_hw_device v []
@@ -185,9 +194,7 @@ driverFunc v _name ilaPath targets = do
     let targetIndex = fromMaybe 9 $ L.findIndex (\di -> di.deviceId == targetId) demoRigInfo
     -- since we're running one test after another we don't need a different port
     let gdbPort = 3333 -- + targetIndex
-
     withOpenOcd d.usbAdapterLocation gdbPort $ \ocd -> do
-
       -- make sure OpenOCD is started properly
 
       hSetBuffering ocd.stderrHandle LineBuffering
@@ -205,7 +212,6 @@ driverFunc v _name ilaPath targets = do
 
       putStrLn "Starting Picocom..."
       withPicocomWithLogging d.serial stdoutLog stderrLog $ \pico -> do
-
         hSetBuffering pico.stdinHandle LineBuffering
         hSetBuffering pico.stdoutHandle LineBuffering
 
@@ -235,7 +241,6 @@ driverFunc v _name ilaPath targets = do
 
         -- program the FPGA
         withGdb $ \gdb -> do
-
           hSetBuffering gdb.stdinHandle LineBuffering
 
           runGdbCommands
@@ -249,7 +254,6 @@ driverFunc v _name ilaPath targets = do
           tryWithTimeout "Waiting for \"load dome\"" 120_000_000
             $ waitForLine gdb.stdoutHandle "load done"
 
-
           -- break test
           do
             putStrLn "Testing whether breakpoints work"
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscvTcp.hs b/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscvTcp.hs
index 7bdbee464..03176993b 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscvTcp.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/Driver/VexRiscvTcp.hs
@@ -178,13 +178,15 @@ driverFunc ::
   VivadoHandle ->
   String ->
   FilePath ->
-  [ ( HwTarget
-    , DeviceInfo
-    , (ProcessStdIoHandles, ProcessStdIoHandles, ProcessStdIoHandles, IO ())
-    )
-  ] ->
+  [(HwTarget, DeviceInfo)] ->
   IO ExitCode
-driverFunc v _name ilaPath [(hwT, _, (_ocd, pico, _gdb, cleanupFn))] = do
+driverFunc v _name ilaPath [(hwT, dI)] = do
+  preProcessResult <- preProcessFunc v _name ilaPath hwT dI
+
+  (_ocd, pico, _gdb, cleanupFn) <- case preProcessResult of
+    TestStepSuccess out -> pure out
+    TestStepFailure reason -> assertFailure $ "test failed. reason: " <> reason
+
   openHwT v hwT
   execCmd_ v "set_property" ["PROBES.FILE", embrace ilaPath, "[current_hw_device]"]
   refresh_hw_device v []
@@ -238,7 +240,7 @@ driverFunc v _name ilaPath [(hwT, _, (_ocd, pico, _gdb, cleanupFn))] = do
 
   cleanupFn
 
-  pure $ ExitSuccess
+  pure ExitSuccess
 driverFunc _v _name _ilaPath _ = error "Ethernet/VexRiscvTcp driver func should only run with one hardware target"
 
 {- | Test that the `Bittide.Instances.Hitl.Ethernet:vexRiscvTcpTest` design programmed
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/Ethernet.hs b/bittide-instances/src/Bittide/Instances/Hitl/Ethernet.hs
index a37bbfd28..ba0dee994 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/Ethernet.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/Ethernet.hs
@@ -89,10 +89,8 @@ tests =
             { name = "VexRiscvTcp"
             , parameters = paramForSingleHwTarget (HwTargetByIndex 7) ()
             , postProcData = ()
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = preProcessFunc
     , mDriverProc = Just driverFunc
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/FincFdec.hs b/bittide-instances/src/Bittide/Instances/Hitl/FincFdec.hs
index cf1b2b541..afd5d8d24 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/FincFdec.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/FincFdec.hs
@@ -25,7 +25,6 @@ import Bittide.Hitl (
   HitlTestGroup (..),
   HwTargetRef (HwTargetByIndex),
   hitlVio,
-  noPreProcess,
   testCasesFromEnum,
  )
 import Bittide.Instances.Domains
@@ -223,7 +222,6 @@ tests =
     , extraXdcFiles = []
     , externalHdl = []
     , testCases = testCasesFromEnum @Test [HwTargetByIndex 7] ()
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/FullMeshHwCc.hs b/bittide-instances/src/Bittide/Instances/Hitl/FullMeshHwCc.hs
index 82c7774ca..10ceeb213 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/FullMeshHwCc.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/FullMeshHwCc.hs
@@ -540,10 +540,8 @@ mkTest topEntity =
                   , clockOffsets = Nothing
                   , startupDelays = toList $ repeat @FpgaCount 0
                   }
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/FullMeshSwCc.hs b/bittide-instances/src/Bittide/Instances/Hitl/FullMeshSwCc.hs
index 4887f563a..408359897 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/FullMeshSwCc.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/FullMeshSwCc.hs
@@ -58,7 +58,7 @@ import Bittide.Transceiver (transceiverPrbsN)
 
 import Bittide.Instances.Hitl.HwCcTopologies (cSigMap, commonSpiConfig, csDupe)
 import Bittide.Instances.Hitl.IlaPlot
-import Bittide.Instances.Hitl.Post.FullMeshSwCc (postProcess, preProcess)
+import Bittide.Instances.Hitl.Post.FullMeshSwCc (postProcess)
 import Bittide.Instances.Hitl.Setup hiding (FpgaCount, LinkCount)
 
 import Clash.Annotations.TH (makeTopEntity)
@@ -713,11 +713,9 @@ tests =
                 , clockOffsets = Nothing
                 , startupDelays = toList $ repeat @FpgaCount 0
                 }
-          , preProc = InheritPreProcess
           }
         | n <- [0 .. testsToRun - 1]
         ]
-    , mPreProc = preProcess
     , mDriverProc = Nothing
     , mPostProc = Just postProcess
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/HwCcTopologies.hs b/bittide-instances/src/Bittide/Instances/Hitl/HwCcTopologies.hs
index be852f34d..5896b5eb4 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/HwCcTopologies.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/HwCcTopologies.hs
@@ -854,7 +854,8 @@ tests = testGroup
   calibrateClockOffsets = calibrateCC False
   validateClockOffsetCalibration = calibrateCC True
 
-  calibrateCC :: Bool -> HitlTestCase HwTargetRef TestConfig CcConf ()
+  -- calibrateCC :: Bool -> HitlTestCase HwTargetRef TestConfig CcConf ()
+  calibrateCC :: Bool -> HitlTestCase HwTargetRef TestConfig CcConf
   calibrateCC validate =
     HitlTestCase
       { name = (if validate then "zzz_validate" else "0_calibrate") <> "_clock_offsets"
@@ -876,7 +877,7 @@ tests = testGroup
             , clockOffsets = Nothing
             , startupDelays = toList $ repeat @FpgaCount 0
             }
-      , preProc = InheritPreProcess
+            -- , preProc = InheritPreProcess
       }
 
   -- tests the given topology
@@ -886,7 +887,8 @@ tests = testGroup
     Maybe (Vec n PartsPer) ->
     Vec n StartupDelay ->
     Topology n ->
-    HitlTestCase HwTargetRef TestConfig CcConf ()
+    -- HitlTestCase HwTargetRef TestConfig CcConf ()
+    HitlTestCase HwTargetRef TestConfig CcConf
   tt clockShifts startDelays t =
     HitlTestCase
       { name = topologyName t
@@ -910,7 +912,7 @@ tests = testGroup
             , clockOffsets = toList <$> clockShifts
             , startupDelays = fromIntegral <$> toList startDelays
             }
-      , preProc = InheritPreProcess
+            -- , preProc = InheritPreProcess
       }
 
   maybeVecToVecMaybe :: forall n a. (KnownNat n) => Maybe (Vec n a) -> Vec n (Maybe a)
@@ -957,7 +959,6 @@ tests = testGroup
           -- make sure the clock offsets detected during calibration is still the same
         , validateClockOffsetCalibration
         ]
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/LinkConfiguration.hs b/bittide-instances/src/Bittide/Instances/Hitl/LinkConfiguration.hs
index 8b115170c..76583aa36 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/LinkConfiguration.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/LinkConfiguration.hs
@@ -285,10 +285,8 @@ tests =
                   | i <- [0 ..] :: [Index FpgaCount]
                   ]
             , postProcData = ()
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/SyncInSyncOut.hs b/bittide-instances/src/Bittide/Instances/Hitl/SyncInSyncOut.hs
index fcf16b711..49d31f71e 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/SyncInSyncOut.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/SyncInSyncOut.hs
@@ -168,10 +168,8 @@ tests =
             { name = "SyncInSyncOut"
             , parameters = paramForHwTargets allHwTargets ()
             , postProcData = ()
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/TemperatureMonitor.hs b/bittide-instances/src/Bittide/Instances/Hitl/TemperatureMonitor.hs
index b1b765008..fcf0bc813 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/TemperatureMonitor.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/TemperatureMonitor.hs
@@ -18,11 +18,9 @@ import Clash.Xilinx.ClockGen (clockWizardDifferential)
 
 import Bittide.Arithmetic.Time (trueFor)
 import Bittide.Hitl (
-  CasePreProcessing (..),
   HitlTestCase (..),
   HitlTestGroup (..),
   hitlVioBool,
-  noPreProcess,
   paramForHwTargets,
  )
 import Bittide.Instances.Hitl.Setup (allHwTargets)
@@ -113,10 +111,8 @@ tests =
             { name = "TemperatureMonitor"
             , parameters = paramForHwTargets allHwTargets ()
             , postProcData = ()
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/Transceivers.hs b/bittide-instances/src/Bittide/Instances/Hitl/Transceivers.hs
index 0b0ef4fd6..1bb524beb 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/Transceivers.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/Transceivers.hs
@@ -233,7 +233,6 @@ tests =
     , externalHdl = []
     , extraXdcFiles = []
     , testCases = iters
-    , mPreProc = noPreProcess
     , mDriverProc = Nothing
     , mPostProc = Nothing
     }
@@ -247,7 +246,6 @@ tests =
       , parameters =
           Map.fromList (L.zip (HwTargetByIndex . fromIntegral <$> fpgaIndices) fpgaIndices)
       , postProcData = ()
-      , preProc = InheritPreProcess
       }
     | nm <- iterNames
     ]
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/Utils/Program.hs b/bittide-instances/src/Bittide/Instances/Hitl/Utils/Program.hs
index 2e13571e0..a9c271d7b 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/Utils/Program.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/Utils/Program.hs
@@ -113,7 +113,6 @@ startPicocom devPath = do
 
   pure (picoHandles', cleanupProcess picoHandles)
 
-
 withPicocomWithLogging ::
   FilePath ->
   FilePath ->
diff --git a/bittide-instances/src/Bittide/Instances/Hitl/VexRiscv.hs b/bittide-instances/src/Bittide/Instances/Hitl/VexRiscv.hs
index e4a648a50..9fccc15af 100644
--- a/bittide-instances/src/Bittide/Instances/Hitl/VexRiscv.hs
+++ b/bittide-instances/src/Bittide/Instances/Hitl/VexRiscv.hs
@@ -164,10 +164,8 @@ tests =
             , parameters =
                 paramForHwTargets [HwTargetByIndex 1, HwTargetByIndex 2] ()
             , postProcData = ()
-            , preProc = InheritPreProcess
             }
         ]
-    , mPreProc = noPreProcess -- preProcessFunc
     , mDriverProc = Just driverFunc
     , mPostProc = Nothing
     }
diff --git a/bittide-shake/src/Clash/Shake/Vivado.hs b/bittide-shake/src/Clash/Shake/Vivado.hs
index e08cc9cf3..3a50ee89a 100644
--- a/bittide-shake/src/Clash/Shake/Vivado.hs
+++ b/bittide-shake/src/Clash/Shake/Vivado.hs
@@ -25,6 +25,7 @@ module Clash.Shake.Vivado (
   runPlaceAndRoute,
   runBitstreamGen,
   runProbesFileGen,
+  pollTestDone,
   programBitstream,
   runHitlTest,
   meetsTiming,
@@ -48,7 +49,7 @@ import Control.Concurrent.MVar (MVar, modifyMVar, newMVar)
 import Control.Exception (try)
 import Control.Monad.Extra (andM, forM, forM_, orM, unless, when)
 import Data.Containers.ListUtils (nubOrd)
-import Data.Either (lefts, partitionEithers, rights)
+import Data.Either (lefts, rights)
 import Data.List (isInfixOf, isSuffixOf, sort, sortOn, (\\))
 import Data.List.Extra (anySame, split, (!?))
 import Data.Map.Strict (fromList, keys, mapKeys, toAscList)
@@ -58,9 +59,9 @@ import Data.Set (Set)
 import qualified Data.Set as Set
 import Data.String.Interpolate (i, __i)
 import Data.Text (unpack)
-import System.Clock (Clock (Monotonic), diffTimeSpec, getTime, toNanoSecs)
+import System.Clock (Clock (Monotonic), TimeSpec, diffTimeSpec, getTime, toNanoSecs)
 import System.Directory (createDirectoryIfMissing)
-import System.Exit (ExitCode (..), exitFailure)
+import System.Exit (ExitCode (..))
 import System.FilePath (dropFileName, (</>))
 import Text.Read (readMaybe)
 import Vivado (TclException (..), VivadoHandle, execPrint_, with)
@@ -661,37 +662,14 @@ verifyHwIlas v = do
 the probe_test_done probe. Returns whether the test case was successful.
 -}
 waitTestCaseEnd ::
-  VivadoHandle -> HitlTestCase (HwTarget, DeviceInfo) a b c -> FilePath -> IO ExitCode
+  VivadoHandle -> HitlTestCase (HwTarget, DeviceInfo) a b -> FilePath -> IO ExitCode
 waitTestCaseEnd v HitlTestCase{..} probesFilePath = do
   startTime <- getTime Monotonic
   let calcTimeSpentMs = (`div` 1000000) . toNanoSecs . diffTimeSpec startTime <$> getTime Monotonic
   exitCodes <- forM (keys parameters) $ \(hwT, _) -> do
     openHwT v hwT
     execCmd_ v "set_property" ["PROBES.FILE", embrace probesFilePath, "[current_hw_device]"]
-    let
-      pollTestDone :: IO ExitCode
-      pollTestDone = do
-        refresh_hw_device v ["-quiet"]
-        timeSpentMs <- calcTimeSpentMs
-        done <- execCmd v "get_property" ["INPUT_VALUE", getProbeTestDoneTcl]
-        success <- execCmd v "get_property" ["INPUT_VALUE", getProbeTestSuccessTcl]
-        case (done, success, timeSpentMs >= testTimeoutMs) of
-          ("1", "1", _) -> do
-            pure ExitSuccess
-          ("1", _, _) -> do
-            putStrLn $ "HITL test case failure for hardware target " <> prettyShow hwT
-            pure (ExitFailure 2)
-          (_, _, True) -> do
-            putStrLn $
-              "HITL test case timeout (≥"
-                <> show testTimeoutMs
-                <> "ms) for hardware target "
-                <> prettyShow hwT
-            pure (ExitFailure 3)
-          _ -> do
-            threadDelay 1000 -- In μs
-            pollTestDone
-    pollTestDone
+    pollTestDone startTime testTimeoutMs v hwT
 
   -- Print summary of test case
   timeSpentMs <- calcTimeSpentMs
@@ -712,6 +690,31 @@ waitTestCaseEnd v HitlTestCase{..} probesFilePath = do
   -- TODO: Allow the user to specify the timeout for a test.
   testTimeoutMs = 60000 :: Integer
 
+pollTestDone :: TimeSpec -> Integer -> VivadoHandle -> HwTarget -> IO ExitCode
+pollTestDone startTime testTimeoutMs v hwT = do
+  refresh_hw_device v ["-quiet"]
+  timeSpentMs <- calcTimeSpentMs
+  done <- execCmd v "get_property" ["INPUT_VALUE", getProbeTestDoneTcl]
+  success <- execCmd v "get_property" ["INPUT_VALUE", getProbeTestSuccessTcl]
+  case (done, success, timeSpentMs >= testTimeoutMs) of
+    ("1", "1", _) -> do
+      pure ExitSuccess
+    ("1", _, _) -> do
+      putStrLn $ "HITL test case failure for hardware target " <> prettyShow hwT
+      pure (ExitFailure 2)
+    (_, _, True) -> do
+      putStrLn $
+        "HITL test case timeout (≥"
+          <> show testTimeoutMs
+          <> "ms) for hardware target "
+          <> prettyShow hwT
+      pure (ExitFailure 3)
+    _ -> do
+      threadDelay 1000 -- In μs
+      pollTestDone startTime testTimeoutMs v hwT
+ where
+  calcTimeSpentMs = (`div` 1000000) . toNanoSecs . diffTimeSpec startTime <$> getTime Monotonic
+
 runHitlTest ::
   -- | The HITL test group to execute
   HitlTestGroup ->
@@ -722,7 +725,7 @@ runHitlTest ::
   -- | Filepath the the ILA data dump directory
   FilePath ->
   IO ExitCode
-runHitlTest test@HitlTestGroup{topEntity, testCases, mPreProc, mDriverProc} url probesFilePath ilaDataDir = do
+runHitlTest test@HitlTestGroup{topEntity, testCases, mDriverProc} url probesFilePath ilaDataDir = do
   putStrLn $
     "Starting HITL test for FPGA design '"
       <> show topEntity
@@ -766,7 +769,7 @@ runHitlTest test@HitlTestGroup{topEntity, testCases, mPreProc, mDriverProc} url
         lookupDeviceInfo key = deviceInfoFromHwTRef key
 
       exitCode <-
-        runHitlTestCase v resolvedTestCase mPreProc mDriverProc probesFilePath ilaDataDir
+        runHitlTestCase v resolvedTestCase mDriverProc probesFilePath ilaDataDir
       pure (name, exitCode)
 
     let failedTestCaseNames = fst <$> filter ((/= ExitSuccess) . snd) testResults
@@ -790,21 +793,19 @@ runHitlTest test@HitlTestGroup{topEntity, testCases, mPreProc, mDriverProc} url
 
 -- | Runs one test case of a HITL test group
 runHitlTestCase ::
-  forall a b c.
+  forall a b.
   -- | Handle to a Vivado object that is to execute the Tcl
   VivadoHandle ->
   -- | The HITL test case to run
-  HitlTestCase (HwTarget, DeviceInfo) a b c ->
-  -- | Pre-process function for the test group
-  (VivadoHandle -> String -> FilePath -> HwTarget -> DeviceInfo -> IO (TestStepResult c)) ->
+  HitlTestCase (HwTarget, DeviceInfo) a b ->
   -- | Driver function
-  Maybe (VivadoHandle -> String -> FilePath -> [(HwTarget, DeviceInfo, c)] -> IO ExitCode) ->
+  Maybe (VivadoHandle -> String -> FilePath -> [(HwTarget, DeviceInfo)] -> IO ExitCode) ->
   -- | Path to the generated probes file
   FilePath ->
   -- | Filepath the the ILA data dump directory
   FilePath ->
   IO ExitCode
-runHitlTestCase v testCase@HitlTestCase{name, parameters, preProc} preProcessFunc driverFunc probesFilePath ilaDataDir = do
+runHitlTestCase v testCase@HitlTestCase{name, parameters} driverFunc probesFilePath ilaDataDir = do
   if null parameters
     then do
       putStrLn
@@ -871,32 +872,7 @@ runHitlTestCase v testCase@HitlTestCase{name, parameters, preProc} preProcessFun
         execCmd_ v "set_property" ["OUTPUT_VALUE", "0", getProbeTestStartTcl]
         commit_hw_vio v ["[get_hw_vios]"]
 
-        -- run pre-processing
-        testRunData <- case preProc of
-          InheritPreProcess -> do
-            putStrLn $
-              "Running test-group pre-process function for "
-                <> name
-                <> " ('"
-                <> prettyShow hwT
-                <> "')"
-            preProcessFunc v name probesFilePath hwT deviceInfo
-          CustomPreProcess f -> do
-            putStrLn $
-              "Running case pre-process function for "
-                <> name
-                <> " ('"
-                <> prettyShow hwT
-                <> "')"
-            f v probesFilePath hwT deviceInfo
-
-        case testRunData of
-          TestStepFailure msg -> do
-            putStrLn $
-              "pre-process step failed: " <> msg
-            pure $ Left (hwT, msg)
-          TestStepSuccess val -> do
-            pure $ Right (hwT, deviceInfo, val)
+        return (hwT, deviceInfo)
 
       -- Assert HitlVio start probe
       -- execCmd_ v "set_property" ["OUTPUT_VALUE", "1", getProbeTestStartTcl]
@@ -905,16 +881,14 @@ runHitlTestCase v testCase@HitlTestCase{name, parameters, preProc} preProcessFun
 
       -- pure testRunData
 
-      let (failedTests, validTests) = partitionEithers testData
-
-      testCaseExitCode0 <- case driverFunc of
+      testCaseExitCode <- case driverFunc of
         Just fn -> do
           putStrLn $ "Running custom driver function for test " <> name
-          fn v name probesFilePath validTests
+          fn v name probesFilePath testData
         Nothing -> do
           putStrLn $ "Running default driver function for test " <> name
 
-          forM_ validTests $ \(hwT, _deviceInfo, _testData) -> do
+          forM_ testData $ \(hwT, _deviceInfo) -> do
             -- Assert HitlVio start probe
             openHwT v hwT
             execCmd_ v "set_property" ["PROBES.FILE", embrace probesFilePath, "[current_hw_device]"]
@@ -927,11 +901,6 @@ runHitlTestCase v testCase@HitlTestCase{name, parameters, preProc} preProcessFun
           putStrLn $ "Waiting for test case '" <> name <> "' to end..."
           waitTestCaseEnd v testCase probesFilePath
 
-      testCaseExitCode <-
-        if null failedTests
-          then pure testCaseExitCode0
-          else exitFailure
-
       putStrLn "Saving captured ILA data (if relevant)..."
       forM_ (keys parameters) $ \(hwT, _) -> do
         openHwT v hwT
diff --git a/bittide-tools/clockcontrol/plot/Main.hs b/bittide-tools/clockcontrol/plot/Main.hs
index 75302d07d..a7bb25c29 100644
--- a/bittide-tools/clockcontrol/plot/Main.hs
+++ b/bittide-tools/clockcontrol/plot/Main.hs
@@ -487,8 +487,10 @@ knownTestsWithCcConf = Map.fromList (mapMaybe go hitlTests)
   justOrDie _ (Just x) = Just x
   justOrDie k Nothing = error $ "No CcConf for " <> show k
 
-  go HitlTestGroup{topEntity, testCases = iters :: [HitlTestCase HwTargetRef q r c]} =
-    case cast @[HitlTestCase HwTargetRef q r c] @[HitlTestCase HwTargetRef q CcConf c] iters of
+  -- go HitlTestGroup{topEntity, testCases = iters :: [HitlTestCase HwTargetRef q r c]} =
+  go HitlTestGroup{topEntity, testCases = iters :: [HitlTestCase HwTargetRef q r]} =
+    -- case cast @[HitlTestCase HwTargetRef q r c] @[HitlTestCase HwTargetRef q CcConf c] iters of
+    case cast @[HitlTestCase HwTargetRef q r] @[HitlTestCase HwTargetRef q CcConf] iters of
       Just q ->
         Just
           ( show topEntity