diff --git a/flake.nix b/flake.nix
index 9225a5dfc..ad7b31dd8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -52,8 +52,8 @@
         hevm = pkgs: pkgs.lib.pipe ((hsPkgs pkgs).callCabal2nix "hevm" (pkgs.fetchFromGitHub {
           owner = "ethereum";
           repo = "hevm";
-          rev = "f1f45d3c0d9767a38df04f398d1eab8b66dbe7fc";
-          sha256 = "sha256-3zEUwcZm4uZZLecvFTgVTV5CAm4qMfKPbLdwO88LnrY=";
+          rev = "dbb014ff7eb84dcfbdd6c278050d59dfe39ef5d0";
+          sha256 = "sha256-d4dKtJoOHpLdwyqBnGI0cHqthP8LCc/HWaguYCefXcQ=";
         }) { secp256k1 = pkgs.secp256k1; })
         ([
           pkgs.haskell.lib.compose.dontCheck
diff --git a/lib/Echidna/SymExec.hs b/lib/Echidna/SymExec.hs
index 9aa5b6bc7..55444f26e 100644
--- a/lib/Echidna/SymExec.hs
+++ b/lib/Echidna/SymExec.hs
@@ -77,7 +77,7 @@ exploreContract conf contract tx vm = do
   doneChan <- newEmptyMVar
   resultChan <- newEmptyMVar
 
-  flip runReaderT defaultEnv $ withSolvers Z3 (fromIntegral conf.campaignConf.symExecNSolvers) timeout $ \solvers -> do
+  flip runReaderT defaultEnv $ withSolvers Z3 (fromIntegral conf.campaignConf.symExecNSolvers) 1 timeout $ \solvers -> do
     threadId <- liftIO $ forkIO $ flip runReaderT defaultEnv $ do
       res <- forM methods $ \method -> do
         let
@@ -108,7 +108,7 @@ exploreContract conf contract tx vm = do
   pure (threadId, resultChan)
 
 -- | Turn the expression returned by `interpret` into into SMT2 values to feed into the solver
-manipulateExprInter :: Bool -> Expr End -> [SMT2]
+manipulateExprInter :: Bool -> Expr End -> [Either String SMT2]
 manipulateExprInter isConc = map (assertProps defaultConfig) . middleStep . map (extractProps . simplify) . flattenExpr . simplify where
   middleStep = if isConc then middleStepConc else id
   middleStepConc = map singleton . concatMap (go (PBool True))
diff --git a/lib/Echidna/Types/Tx.hs b/lib/Echidna/Types/Tx.hs
index ea844eec0..7ff01d192 100644
--- a/lib/Echidna/Types/Tx.hs
+++ b/lib/Echidna/Types/Tx.hs
@@ -234,7 +234,7 @@ getResult = \case
   VMFailure BadJumpDestination            -> ErrorBadJumpDestination
   VMFailure (Revert _)                    -> ErrorRevert
   VMFailure (OutOfGas _ _)                -> ErrorOutOfGas
-  VMFailure (BadCheatCode _)              -> ErrorBadCheatCode
+  VMFailure (BadCheatCode _ _)            -> ErrorBadCheatCode
   VMFailure StackLimitExceeded            -> ErrorStackLimitExceeded
   VMFailure IllegalOverflow               -> ErrorIllegalOverflow
   VMFailure StateChangeWhileStatic        -> ErrorStateChangeWhileStatic
diff --git a/stack.yaml b/stack.yaml
index 12c0d0699..02c5ec9a4 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -5,7 +5,7 @@ packages:
 
 extra-deps:
 - git: https://github.com/ethereum/hevm.git
-  commit: f1f45d3c0d9767a38df04f398d1eab8b66dbe7fc
+  commit: dbb014ff7eb84dcfbdd6c278050d59dfe39ef5d0
 
 - smt2-parser-0.1.0.1@sha256:1e1a4565915ed851c13d1e6b8bb5185cf5d454da3b43170825d53e221f753d77,1421
 - spawn-0.3@sha256:b91e01d8f2b076841410ae284b32046f91471943dc799c1af77d666c72101f02,1162