diff --git a/fluffy/data/history_data_parser.nim b/fluffy/data/history_data_parser.nim
index b25f9e863..c77f93764 100644
--- a/fluffy/data/history_data_parser.nim
+++ b/fluffy/data/history_data_parser.nim
@@ -83,7 +83,7 @@ func readBlockData*(
       $blockData.number & ": " & e.msg)
 
   let contentKeyType =
-    BlockKey(chainId: 1'u16, blockHash: blockHash)
+    BlockKey(blockHash: blockHash)
 
   try:
     # If wanted the hash for the corresponding header can be verified
diff --git a/fluffy/network/history/history_content.nim b/fluffy/network/history/history_content.nim
index de2611643..754b09cfd 100644
--- a/fluffy/network/history/history_content.nim
+++ b/fluffy/network/history/history_content.nim
@@ -18,12 +18,13 @@ import
 export ssz_serialization, common_types, hash
 
 ## Types and calls for history network content keys
+
 const
-  # Maximum content key size comes from:
-  # 34 bytes for ssz serialized BlockKey
-  # 1 byte for contentType
-  # TODO it would be nice to caluclate it somehow from the object definition (macro?)
-  maxContentKeySize* = 35
+  # Maximum content key size:
+  # - 32 bytes for SSZ serialized `BlockKey`
+  # - 1 byte for `ContentType`
+  # TODO: calculate it somehow from the object definition (macro?)
+  maxContentKeySize* = 33
 
 type
   ContentType* = enum
@@ -34,7 +35,6 @@ type
     masterAccumulator = 0x04
 
   BlockKey* = object
-    chainId*: uint16
     blockHash*: BlockHash
 
   EpochAccumulatorKey* = object
@@ -85,7 +85,7 @@ func `$`*(x: BlockHash): string =
   "0x" & x.data.toHex()
 
 func `$`*(x: BlockKey): string =
-  "blockHash: " & $x.blockHash & ", chainId: " & $x.chainId
+  "blockHash: " & $x.blockHash
 
 func `$`*(x: ContentKey): string =
   var res = "(type: " & $x.contentType & ", "
diff --git a/fluffy/network/history/history_network.nim b/fluffy/network/history/history_network.nim
index 8ec748d4e..84c090a20 100644
--- a/fluffy/network/history/history_network.nim
+++ b/fluffy/network/history/history_network.nim
@@ -52,9 +52,9 @@ func encodeKey(k: ContentKey): (ByteList, ContentId) =
   return (keyEncoded, toContentId(keyEncoded))
 
 func getEncodedKeyForContent(
-    cType: ContentType, chainId: uint16, hash: BlockHash):
+    cType: ContentType, hash: BlockHash):
     (ByteList, ContentId) =
-  let contentKeyType = BlockKey(chainId: chainId, blockHash: hash)
+  let contentKeyType = BlockKey(blockHash: hash)
 
   let contentKey =
     case cType
@@ -296,10 +296,10 @@ const requestRetries = 4
 # however that response is not yet validated at that moment.
 
 proc getBlockHeader*(
-    n: HistoryNetwork, chainId: uint16, hash: BlockHash):
+    n: HistoryNetwork, hash: BlockHash):
     Future[Option[BlockHeader]] {.async.} =
   let (keyEncoded, contentId) =
-    getEncodedKeyForContent(blockHeader, chainId, hash)
+    getEncodedKeyForContent(blockHeader, hash)
 
   let headerFromDb = n.getContentFromDb(BlockHeader, contentId)
   if headerFromDb.isSome():
@@ -335,7 +335,7 @@ proc getBlockHeader*(
   return none(BlockHeader)
 
 proc getBlockBody*(
-    n: HistoryNetwork, chainId: uint16, hash: BlockHash, header: BlockHeader):
+    n: HistoryNetwork, hash: BlockHash, header: BlockHeader):
     Future[Option[BlockBody]] {.async.} =
 
   # Got header with empty body, no need to make any db calls or network requests
@@ -343,7 +343,7 @@ proc getBlockBody*(
     return some(BlockBody(transactions: @[], uncles: @[]))
 
   let
-    (keyEncoded, contentId) = getEncodedKeyForContent(blockBody, chainId, hash)
+    (keyEncoded, contentId) = getEncodedKeyForContent(blockBody, hash)
     bodyFromDb = n.getContentFromDb(BlockBody, contentId)
 
   if bodyFromDb.isSome():
@@ -381,11 +381,11 @@ proc getBlockBody*(
   return none(BlockBody)
 
 proc getBlock*(
-    n: HistoryNetwork, chainId: uint16, hash: BlockHash):
+    n: HistoryNetwork, hash: BlockHash):
     Future[Option[Block]] {.async.} =
   debug "Trying to retrieve block with hash", hash
 
-  let headerOpt = await n.getBlockHeader(chainId, hash)
+  let headerOpt = await n.getBlockHeader(hash)
   if headerOpt.isNone():
     warn "Failed to get header when getting block with hash", hash
     # Cannot validate block without header.
@@ -393,7 +393,7 @@ proc getBlock*(
 
   let header = headerOpt.unsafeGet()
 
-  let bodyOpt = await n.getBlockBody(chainId, hash, header)
+  let bodyOpt = await n.getBlockBody(hash, header)
 
   if bodyOpt.isNone():
     warn "Failed to get body when gettin block with hash", hash
@@ -405,14 +405,13 @@ proc getBlock*(
 
 proc getReceipts*(
     n: HistoryNetwork,
-    chainId: uint16,
     hash: BlockHash,
     header: BlockHeader): Future[Option[seq[Receipt]]] {.async.} =
   if header.receiptRoot == EMPTY_ROOT_HASH:
     # Short path for empty receipts indicated by receipts root
     return some(newSeq[Receipt]())
 
-  let (keyEncoded, contentId) = getEncodedKeyForContent(receipts, chainId, hash)
+  let (keyEncoded, contentId) = getEncodedKeyForContent(receipts, hash)
 
   let receiptsFromDb = n.getContentFromDb(seq[Receipt], contentId)
 
@@ -503,7 +502,7 @@ proc getEpochAccumulator(
   return none(EpochAccumulator)
 
 proc getBlock*(
-    n: HistoryNetwork, chainId: uint16, bn: UInt256):
+    n: HistoryNetwork, bn: UInt256):
     Future[Result[Option[Block], string]] {.async.} =
 
   # TODO for now checking accumulator only in db, we could also ask our
@@ -520,7 +519,7 @@ proc getBlock*(
   case hashResponse.kind
   of BHash:
     # we got header hash in current epoch accumulator, try to retrieve it from network
-    let blockResponse = await n.getBlock(chainId, hashResponse.blockHash)
+    let blockResponse = await n.getBlock(hashResponse.blockHash)
     return ok(blockResponse)
   of HEpoch:
     let digest = Digest(data: hashResponse.epochHash)
@@ -534,7 +533,7 @@ proc getBlock*(
       epoch = epochOpt.unsafeGet()
       blockHash = epoch[hashResponse.blockRelativeIndex].blockHash
 
-    let maybeBlock = await n.getBlock(chainId, blockHash)
+    let maybeBlock = await n.getBlock(blockHash)
 
     return ok(maybeBlock)
   of UnknownBlockNumber:
@@ -657,8 +656,7 @@ proc validateContent(
     else:
       return true
   of blockBody:
-    let headerOpt = await n.getBlockHeader(
-      key.blockBodyKey.chainId, key.blockBodyKey.blockHash)
+    let headerOpt = await n.getBlockHeader(key.blockBodyKey.blockHash)
 
     if headerOpt.isNone():
       warn "Cannot find the header, no way to validate the block body"
@@ -680,8 +678,7 @@ proc validateContent(
     else:
       return true
   of receipts:
-    let headerOpt = await n.getBlockHeader(
-      key.receiptsKey.chainId, key.receiptsKey.blockHash)
+    let headerOpt = await n.getBlockHeader(key.receiptsKey.blockHash)
 
     if headerOpt.isNone():
       warn "Cannot find the header, no way to validate the receipts"
diff --git a/fluffy/rpc/rpc_eth_api.nim b/fluffy/rpc/rpc_eth_api.nim
index 2b6dd7283..3de74ca01 100644
--- a/fluffy/rpc/rpc_eth_api.nim
+++ b/fluffy/rpc/rpc_eth_api.nim
@@ -203,7 +203,7 @@ proc installEthApiHandlers*(
     ## Returns BlockObject or nil when no block was found.
     let
       blockHash = data.toHash()
-      blockRes = await historyNetwork.getBlock(1'u16, blockHash)
+      blockRes = await historyNetwork.getBlock(blockHash)
 
     if blockRes.isNone():
       return none(BlockObject)
@@ -222,7 +222,7 @@ proc installEthApiHandlers*(
 
     let
       blockNumber = fromHex(UInt256, quantityTag)
-      blockResult = await historyNetwork.getBlock(1'u16, blockNumber)
+      blockResult = await historyNetwork.getBlock(blockNumber)
 
     if blockResult.isOk():
       let maybeBlock = blockResult.get()
@@ -244,7 +244,7 @@ proc installEthApiHandlers*(
     ## Returns integer of the number of transactions in this block.
     let
       blockHash = data.toHash()
-      blockRes = await historyNetwork.getBlock(1'u16, blockHash)
+      blockRes = await historyNetwork.getBlock(blockHash)
 
     if blockRes.isNone():
       raise newException(ValueError, "Could not find block with requested hash")
@@ -273,7 +273,7 @@ proc installEthApiHandlers*(
     else:
       let hash = filterOptions.blockHash.unsafeGet()
 
-      let headerOpt = await historyNetwork.getBlockHeader(1'u16, hash)
+      let headerOpt = await historyNetwork.getBlockHeader(hash)
       if headerOpt.isNone():
         raise newException(ValueError,
           "Could not find header with requested hash")
@@ -285,8 +285,8 @@ proc installEthApiHandlers*(
         # are no assumptions about usage of concurrent queries on portal
         # wire protocol level
         let
-          bodyOpt = await historyNetwork.getBlockBody(1'u16, hash, header)
-          receiptsOpt = await historyNetwork.getReceipts(1'u16, hash, header)
+          bodyOpt = await historyNetwork.getBlockBody(hash, header)
+          receiptsOpt = await historyNetwork.getReceipts(hash, header)
 
         if bodyOpt.isSome() and receiptsOpt.isSome():
           let
diff --git a/fluffy/tests/test_history_content.nim b/fluffy/tests/test_history_content.nim
index c803a5e69..1143be02f 100644
--- a/fluffy/tests/test_history_content.nim
+++ b/fluffy/tests/test_history_content.nim
@@ -23,16 +23,16 @@ suite "History ContentKey Encodings":
     # Output
     const
       contentKeyHex =
-        "000f00d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
+        "00d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
       contentId =
-        "15025167517633317571792618561170587584740338038067807801482118109695980329625"
+        "28281392725701906550238743427348001871342819822834514257505083923073246729726"
       # or
       contentIdHexBE =
-        "2137f185b713a60dd1190e650d01227b4f94ecddc9c95478e2c591c40557da99"
+        "3e86b3767b57402ea72e369ae0496ce47cc15be685bec3b4726b9f316e3895fe"
 
     let contentKey = ContentKey(
       contentType: blockHeader,
-      blockHeaderKey: BlockKey(chainId: 15'u16, blockHash: blockHash))
+      blockHeaderKey: BlockKey(blockHash: blockHash))
 
     let encoded = encode(contentKey)
     check encoded.asSeq.toHex == contentKeyHex
@@ -56,16 +56,16 @@ suite "History ContentKey Encodings":
     # Output
     const
       contentKeyHex =
-        "011400d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
+        "01d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
       contentId =
-        "12834862124958403129911294156243112356210437741210740000860318140844473844426"
+        "106696502175825986237944249828698290888857178633945273402044845898673345165419"
       # or
       contentIdHexBE =
-        "1c6046475f0772132774ab549173ca8487bea031ce539cad8e990c08df5802ca"
+        "ebe414854629d60c58ddd5bf60fd72e41760a5f7a463fdcb169f13ee4a26786b"
 
     let contentKey = ContentKey(
       contentType: blockBody,
-      blockBodyKey: BlockKey(chainId: 20'u16, blockHash: blockHash))
+      blockBodyKey: BlockKey(blockHash: blockHash))
 
     let encoded = encode(contentKey)
     check encoded.asSeq.toHex == contentKeyHex
@@ -89,16 +89,16 @@ suite "History ContentKey Encodings":
     # Output
     const
       contentKeyHex =
-        "020400d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
+        "02d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
       contentId =
-        "76995449220721979583200368506411933662679656077191192504502358532083948020658"
+        "76230538398907151249589044529104962263309222250374376758768131420767496438948"
       # or
       contentIdHexBE =
-        "aa39e1423e92f5a667ace5b79c2c98adbfd79c055d891d0b9c49c40f816563b2"
+        "a888f4aafe9109d495ac4d4774a6277c1ada42035e3da5e10a04cc93247c04a4"
 
     let contentKey = ContentKey(
       contentType: receipts,
-      receiptsKey: BlockKey(chainId: 4'u16, blockHash: blockHash))
+      receiptsKey: BlockKey(blockHash: blockHash))
 
     let encoded = encode(contentKey)
     check encoded.asSeq.toHex == contentKeyHex
diff --git a/fluffy/tests/test_history_network.nim b/fluffy/tests/test_history_network.nim
index 3e85dddca..46a4222d5 100644
--- a/fluffy/tests/test_history_network.nim
+++ b/fluffy/tests/test_history_network.nim
@@ -63,7 +63,7 @@ proc headersToContentInfo(headers: seq[BlockHeader]): seq[ContentInfo] =
   for h in headers:
     let
       headerHash = h.blockHash()
-      bk = BlockKey(chainId: 1'u16, blockHash: headerHash)
+      bk = BlockKey(blockHash: headerHash)
       ck = encode(ContentKey(contentType: blockHeader, blockHeaderKey: bk))
       headerEncoded = rlp.encode(h)
       ci = ContentInfo(contentKey: ck, content: headerEncoded)
@@ -96,7 +96,7 @@ procSuite "History Content Network":
     for h in headers:
       let
         headerHash = h.blockHash()
-        blockKey = BlockKey(chainId: 1'u16, blockHash: headerHash)
+        blockKey = BlockKey(blockHash: headerHash)
         contentKey = ContentKey(
           contentType: blockHeader, blockHeaderKey: blockKey)
         contentId = toContentId(contentKey)
@@ -116,7 +116,7 @@ procSuite "History Content Network":
       (await historyNode2.portalProtocol().ping(historyNode1.localNode())).isOk()
 
     for i in 0..lastBlockNumber:
-      let blockResponse = await historyNode1.historyNetwork.getBlock(1'u16, u256(i))
+      let blockResponse = await historyNode1.historyNetwork.getBlock(u256(i))
 
       check blockResponse.isOk()
 
diff --git a/fluffy/tools/eth_data_exporter.nim b/fluffy/tools/eth_data_exporter.nim
index 31200fe59..f98876565 100644
--- a/fluffy/tools/eth_data_exporter.nim
+++ b/fluffy/tools/eth_data_exporter.nim
@@ -294,7 +294,7 @@ proc writeBlocksToDb(config: ExporterConf, client: RpcClient) =
     let
       blck = downloadBlock(i, client)
       blockHash = blck.header.blockHash()
-      contentKeyType = BlockKey(chainId: 1, blockHash: blockHash)
+      contentKeyType = BlockKey(blockHash: blockHash)
       headerKey = encode(ContentKey(
         contentType: blockHeader, blockHeaderKey: contentKeyType))
       bodyKey = encode(ContentKey(