diff --git a/eth/common/eth_types.nim b/eth/common/eth_types.nim
index 73fc487..96122bd 100644
--- a/eth/common/eth_types.nim
+++ b/eth/common/eth_types.nim
@@ -99,6 +99,7 @@ type
     address*       : EthAddress
     amount*        : uint64
 
+  # https://eips.ethereum.org/EIPS/eip-4844#header-extension
   BlockHeader* = object
     parentHash*:      Hash256
     ommersHash*:      Hash256
@@ -118,7 +119,8 @@ type
     # `baseFee` is the get/set of `fee`
     fee*:             Option[UInt256]   # EIP-1559
     withdrawalsRoot*: Option[Hash256]   # EIP-4895
-    excessDataGas*:   Option[UInt256]   # EIP-4844
+    dataGasUsed*:     Option[uint64]    # EIP-4844
+    excessDataGas*:   Option[uint64]    # EIP-4844
 
   BlockBody* = object
     transactions*:  seq[Transaction]
diff --git a/eth/p2p/discovery.nim b/eth/p2p/discovery.nim
index ea42c7b..3788975 100644
--- a/eth/p2p/discovery.nim
+++ b/eth/p2p/discovery.nim
@@ -87,7 +87,7 @@ proc recoverMsgPublicKey(msg: openArray[byte]): DiscResult[PublicKey] =
 
 proc unpack(msg: openArray[byte]): tuple[cmdId: CommandId, payload: seq[byte]]
     {.raises: [DiscProtocolError].} =
-  # Check against possible RangeError
+  # Check against possible RangeDefect
   if msg[HEAD_SIZE].int < CommandId.low.ord or
      msg[HEAD_SIZE].int > CommandId.high.ord:
     raise newException(DiscProtocolError, "Unsupported packet id")
diff --git a/eth/trie/nibbles.nim b/eth/trie/nibbles.nim
index 3e9928b..10332ad 100644
--- a/eth/trie/nibbles.nim
+++ b/eth/trie/nibbles.nim
@@ -11,7 +11,7 @@ proc initNibbleRange*(bytes: openArray[byte]): NibblesSeq =
 proc `{}`(r: NibblesSeq, pos: int): byte {.inline.} =
   ## This is a helper for a more raw access to the nibbles.
   ## It works with absolute positions.
-  if pos > r.iend: raise newException(RangeError, "index out of range")
+  if pos > r.iend: raise newException(RangeDefect, "index out of range")
   return if (pos and 1) != 0: (r.bytes[pos div 2] and 0xf)
          else: (r.bytes[pos div 2] shr 4)
 
diff --git a/tests/rlp/test_common.nim b/tests/rlp/test_common.nim
index 05ecf23..886911a 100644
--- a/tests/rlp/test_common.nim
+++ b/tests/rlp/test_common.nim
@@ -116,7 +116,8 @@ proc suite2() =
       doTest h
 
       # EIP-4844
-      h.excessDataGas = some 1234.u256
+      h.dataGasUsed = some 1234'u64
+      h.excessDataGas = some 1234'u64
       doTest h
 
 suite1()
diff --git a/tests/rlp/test_rlp_codec.nim b/tests/rlp/test_rlp_codec.nim
index 25ac586..4819e30 100644
--- a/tests/rlp/test_rlp_codec.nim
+++ b/tests/rlp/test_rlp_codec.nim
@@ -64,14 +64,16 @@ suite "BlockHeader roundtrip test":
   test "Header + none(baseFee) + some(withdrawalsRoot) + some(excessDataGas)":
     let h = BlockHeader(
       withdrawalsRoot: some(Hash256()),
-      excessDataGas: some(1.u256)
+      dataGasUsed: some(1'u64),
+      excessDataGas: some(1'u64)
     )
     expect AssertionDefect:
       roundTrip(h)
 
   test "Header + none(baseFee) + none(withdrawalsRoot) + some(excessDataGas)":
     let h = BlockHeader(
-      excessDataGas: some(1.u256)
+      dataGasUsed: some(1'u64),
+      excessDataGas: some(1'u64)
     )
     expect AssertionDefect:
       roundTrip(h)
@@ -79,7 +81,8 @@ suite "BlockHeader roundtrip test":
   test "Header + some(baseFee) + none(withdrawalsRoot) + some(excessDataGas)":
     let h = BlockHeader(
       fee: some(2.u256),
-      excessDataGas: some(1.u256)
+      dataGasUsed: some(1'u64),
+      excessDataGas: some(1'u64)
     )
     expect AssertionDefect:
       roundTrip(h)
@@ -95,7 +98,8 @@ suite "BlockHeader roundtrip test":
     let h = BlockHeader(
       fee: some(2.u256),
       withdrawalsRoot: some(Hash256()),
-      excessDataGas: some(1.u256)
+      dataGasUsed: some(1'u64),
+      excessDataGas: some(1'u64)
     )
     roundTrip(h)
 
@@ -173,7 +177,8 @@ type
     nonce*:           BlockNonce
     fee*:             Opt[UInt256]
     withdrawalsRoot*: Opt[Hash256]
-    excessDataGas*:   Opt[UInt256]
+    dataGasUsed*:     Opt[GasInt]
+    excessDataGas*:   Opt[GasInt]
 
   BlockBodyOpt* = object
     transactions*:  seq[Transaction]