diff --git a/lib/jormungandr/cardano-wallet-jormungandr.cabal b/lib/jormungandr/cardano-wallet-jormungandr.cabal
index c67d86f2d70..0d258529a46 100644
--- a/lib/jormungandr/cardano-wallet-jormungandr.cabal
+++ b/lib/jormungandr/cardano-wallet-jormungandr.cabal
@@ -34,11 +34,9 @@ library
   build-depends:
       base
     , cardano-wallet-core
---    , binary
---    , bytestring
---    , cardano-crypto
---    , cryptonite
---    , digest
+    , binary
+    , bytestring
+    , memory
     , text
     , text-class
   hs-source-dirs:
diff --git a/lib/jormungandr/src/Cardano/Wallet/Binary/Jormungandr.hs b/lib/jormungandr/src/Cardano/Wallet/Binary/Jormungandr.hs
index b41fec73eb7..abec909742b 100644
--- a/lib/jormungandr/src/Cardano/Wallet/Binary/Jormungandr.hs
+++ b/lib/jormungandr/src/Cardano/Wallet/Binary/Jormungandr.hs
@@ -1,5 +1,8 @@
 {-# LANGUAGE DataKinds #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE TypeApplications #-}
 
 -- |
 -- Copyright: © 2018-2019 IOHK
@@ -8,5 +11,173 @@
 -- The format is for the Shelley era as implemented by the Jörmungandr node.
 
 module Cardano.Wallet.Binary.Jormungandr
-    (
+    ( getBlockHeader
+    , Message (..)
+    , BlockHeader (..)
+
+     -- * Re-export
+    , runGet
+
+    -- * For dev
+    , genesisBlock
+    , dev
     ) where
+
+import Prelude
+
+import Cardano.Wallet.Primitive.Types
+    ( SlotId (..) )
+import Data.Binary.Get
+    ( Get
+    , getByteString
+    , getWord16be
+    , getWord32be
+    , getWord8
+    , isEmpty
+    , isolate
+    , runGet
+    , skip
+    )
+import Data.ByteArray.Encoding
+    ( Base (Base16), convertFromBase )
+import Data.ByteString
+    ( ByteString )
+import Data.Word
+    ( Word16, Word32 )
+
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy as BL
+
+
+-- | Messages is what the block body consists of.
+--
+-- Every message is prefixed with a message header.
+--
+--  Following, as closely as possible:
+-- https://github.com/input-output-hk/rust-cardano/blob/e0616f13bebd6b908320bddb1c1502dea0d3305a/chain-impl-mockchain/src/message/mod.rs#L22-L29
+data Message
+    = Initial [ConfigParam]
+    | OldUtxoDeclaration TODO
+    | Transaction TODO
+    | Certificate TODO
+    | UpdateProposal SignedUpdateProposal
+    | UpdateVote SignedVote
+    | UnimplementedMessage Int -- For development. Remove later.
+    deriving Show
+
+
+data BlockHeader = BlockHeader
+    { version :: Word16
+    , contentSize :: Word32
+    , slot :: SlotId
+    , chainLength :: Word32
+    , contentHash :: ByteString
+    , parentHeaderHash :: Maybe ByteString
+    } deriving (Show, Eq)
+
+data Block = Block BlockHeader [Message]
+    deriving Show
+
+
+data SignedUpdateProposal = SignedUpdateProposal
+    deriving Show
+data TODO = TODO
+    deriving Show
+data SignedVote = SignedVote
+    deriving Show
+data ConfigParam = ConfigParam
+    deriving Show
+
+{-# ANN getBlockHeader ("HLint: ignore Use <$>" :: String) #-}
+getBlockHeader :: Get BlockHeader
+getBlockHeader =  (fromIntegral <$> getWord16be) >>= \s -> isolate s $ do
+    version <- getWord16be
+    sizeOfContent <- getWord32be
+
+    slotEpoch <- fromIntegral <$> getWord32be
+    slotId <- fromIntegral <$> getWord32be
+
+    chainLength <- getWord32be
+
+    contentHash <- getByteString 32 -- or 256 bits
+
+    parentHeaderHash <- getParentHeaderHash
+
+    -- TODO: Handle special case for BFT
+    -- TODO: Handle special case for Praos/Genesis
+
+    return $
+        BlockHeader
+            version
+            sizeOfContent
+            (SlotId slotId slotEpoch)
+            chainLength
+            contentHash
+            parentHeaderHash
+
+getBlock :: Get Block
+getBlock = do
+    header <- getBlockHeader
+    msgs <- isolate (fromIntegral $ contentSize header)
+        $ whileM (not <$> isEmpty) getBlockContent
+    return $ Block header msgs
+
+getBlockContent :: Get Message
+getBlockContent = do
+    size <- getWord16be
+    contentType <- fromIntegral <$> getWord8
+
+    let msgSize = fromIntegral size - 1
+
+    let unimpl = skip msgSize >> return (UnimplementedMessage contentType)
+
+    isolate msgSize $ case contentType of
+        0 -> unimpl
+        1 -> unimpl
+        2 -> unimpl
+        3 -> unimpl
+        4 -> unimpl
+        5 -> unimpl
+        other -> fail $ "Unexpected content type tag " ++ show other
+
+getParentHeaderHash :: Get (Maybe ByteString)
+getParentHeaderHash = getByteString 32 >>= \case
+    a | a == BS.pack (replicate 32 0)
+        -> return Nothing
+      | otherwise
+        -> return $ Just a
+
+
+{-------------------------------------------------------------------------------
+                            For development
+-------------------------------------------------------------------------------}
+
+dev :: IO ()
+dev = print $ runGet getBlock genesisBlock
+
+genesisBlock :: BL.ByteString
+genesisBlock = either error BL.fromStrict $ convertFromBase @ByteString Base16
+    "005200000000009f000000000000000000000000ffadebfecd59d9eaa12e903a\
+    \d58100f7c1e35899739c3d05d022835c069d2b4f000000000000000000000000\
+    \00000000000000000000000000000000000000000047000048000000005cc1c2\
+    \4900810200c200010108000000000000087001410f01840000000a01e030a694\
+    \b80dbba2d1b8a4b55652b03d96315c8414b054fa737445ac2d2a865c76002604\
+    \0001000000ff0005000006000000000000000000000000000000000000000000\
+    \0000000000002c020001833324c37869c122689a35917df53a4f2294a3a52f68\
+    \5e05f5f8e53b87e7ea452f000000000000000e"
+
+
+{-------------------------------------------------------------------------------
+                              Helpers
+-------------------------------------------------------------------------------}
+
+whileM :: Monad m => m Bool -> m a -> m [a]
+whileM p f = go
+  where
+    go = do
+        x <- p
+        if x then do
+            x' <- f
+            xs <- go
+            return (x' : xs)
+        else return []
diff --git a/lib/jormungandr/test/unit/Cardano/Wallet/Binary/JormungandrSpec.hs b/lib/jormungandr/test/unit/Cardano/Wallet/Binary/JormungandrSpec.hs
index 2a5eb1fc889..6501738f321 100644
--- a/lib/jormungandr/test/unit/Cardano/Wallet/Binary/JormungandrSpec.hs
+++ b/lib/jormungandr/test/unit/Cardano/Wallet/Binary/JormungandrSpec.hs
@@ -2,39 +2,41 @@
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE TypeApplications #-}
 
-module Cardano.Wallet.Binary.JormungandrSpec
-    ( spec
-    ) where
+module Cardano.Wallet.Binary.JormungandrSpec (spec) where
 
 import Prelude
 
 import Cardano.Wallet.Binary.Jormungandr
-    ()
-import Data.ByteString
-    ( ByteString )
-
+    ( BlockHeader (..), getBlockHeader, runGet )
 import Cardano.Wallet.Primitive.Types
-    ( BlockHeader (..), Hash (..), SlotId (..) )
-
+    ( SlotId (..) )
 import Data.ByteArray.Encoding
     ( Base (Base16), convertFromBase )
+import Data.ByteString
+    ( ByteString )
 import Test.Hspec
-    ( Spec, describe, shouldBe, xit )
+    ( Spec, describe, it, shouldBe )
+
+import qualified Data.ByteString.Lazy as BL
 
 {-# ANN spec ("HLint: ignore Use head" :: String) #-}
 spec :: Spec
 spec = do
     describe "Decoding blocks" $ do
-        xit "should decode a genesis block" $ do
-            unsafeDeserialiseFromBytes decodeGenesisBlock genesisBlock
+        it "should decode a genesis block header" $ do
+            runGet getBlockHeader genesisBlock
             `shouldBe`
-            BlockHeader (SlotId 0 0) (Hash "?")
-  where
-    unsafeDeserialiseFromBytes = undefined
-    decodeGenesisBlock = error "TODO: import from Binary.Jormungandr"
+            (BlockHeader
+                { version = 0
+                , contentSize = 159
+                , slot = SlotId {epochNumber = 0 , slotNumber = 0}
+                , chainLength = 0
+                , contentHash = "\255\173\235\254\205Y\217\234\161.\144:\213\129\NUL\247\193\227X\153s\156=\ENQ\208\"\131\\\ACK\157+O"
+                , parentHeaderHash = Nothing
+                })
 
-genesisBlock :: ByteString
-genesisBlock = either error id $ convertFromBase @ByteString Base16
+genesisBlock :: BL.ByteString
+genesisBlock = either error BL.fromStrict $ convertFromBase @ByteString Base16
     "005200000000009f000000000000000000000000ffadebfecd59d9eaa12e903a\
     \d58100f7c1e35899739c3d05d022835c069d2b4f000000000000000000000000\
     \00000000000000000000000000000000000000000047000048000000005cc1c2\