diff --git a/cardano-crypto-class/src/Cardano/Crypto/KES/CompactSum.hs b/cardano-crypto-class/src/Cardano/Crypto/KES/CompactSum.hs
index a7a7695414..6bb51c478f 100644
--- a/cardano-crypto-class/src/Cardano/Crypto/KES/CompactSum.hs
+++ b/cardano-crypto-class/src/Cardano/Crypto/KES/CompactSum.hs
@@ -514,5 +514,5 @@ instance (HashAlgorithm h)
     fptr <- mallocForeignPtrBytes len
     withForeignPtr fptr $ \ptr -> do
       pull (castPtr ptr) len
-    let bs = BS.fromForeignPtr0 fptr len
+    let bs = BS.fromForeignPtr fptr 0 len
     maybe (error "Invalid hash") return $! VerKeyCompactSumKES <$!> hashFromBytes bs
diff --git a/cardano-crypto-class/src/Cardano/Crypto/KES/Mock.hs b/cardano-crypto-class/src/Cardano/Crypto/KES/Mock.hs
index a3239d9693..3c6941de5a 100644
--- a/cardano-crypto-class/src/Cardano/Crypto/KES/Mock.hs
+++ b/cardano-crypto-class/src/Cardano/Crypto/KES/Mock.hs
@@ -215,7 +215,7 @@ instance (KnownNat t) => DirectDeserialise (SignKeyKES (MockKES t)) where
     fptr <- mallocForeignPtrBytes len
     withForeignPtr fptr $ \ptr ->
         pull (castPtr ptr) (fromIntegral len)
-    let bs = BS.fromForeignPtr0 fptr len
+    let bs = BS.fromForeignPtr fptr 0 len
     maybe (error "directDeserialise @(SignKeyKES (MockKES t))") return $
         rawDeserialiseSignKeyMockKES bs
 
@@ -230,6 +230,6 @@ instance (KnownNat t) => DirectDeserialise (VerKeyKES (MockKES t)) where
     fptr <- mallocForeignPtrBytes len
     withForeignPtr fptr $ \ptr ->
         pull (castPtr ptr) (fromIntegral len)
-    let bs = BS.fromForeignPtr0 fptr len
+    let bs = BS.fromForeignPtr fptr 0 len
     maybe (error "directDeserialise @(VerKeyKES (MockKES t))") return $
         rawDeserialiseVerKeyKES bs
diff --git a/cardano-crypto-class/src/Cardano/Crypto/KES/Sum.hs b/cardano-crypto-class/src/Cardano/Crypto/KES/Sum.hs
index 7f9add51d9..b2206419e5 100644
--- a/cardano-crypto-class/src/Cardano/Crypto/KES/Sum.hs
+++ b/cardano-crypto-class/src/Cardano/Crypto/KES/Sum.hs
@@ -434,5 +434,5 @@ instance (HashAlgorithm h)
     fptr <- mallocForeignPtrBytes len
     withForeignPtr fptr $ \ptr -> do
       pull (castPtr ptr) len
-    let bs = BS.fromForeignPtr0 fptr len
+    let bs = BS.fromForeignPtr fptr 0 len
     maybe (error "Invalid hash") return $! VerKeySumKES <$!> hashFromBytes bs