diff --git a/stateless/tree_from_witness.nim b/stateless/tree_from_witness.nim
index d83677cef..54af337da 100644
--- a/stateless/tree_from_witness.nim
+++ b/stateless/tree_from_witness.nim
@@ -65,9 +65,8 @@ template read(t: var TreeBuilder, len: int): auto =
   toOpenArray(t.data, pos, pos + len - 1)
 ]#
 
-proc readU32(t: var TreeBuilder): int =
-  # TODO: what if the value overflow int32.high?
-  result = fromBytesLE(uint32, t.read(4)).int
+proc readU32(t: var TreeBuilder): uint32 =
+  result = fromBytesBE(uint32, t.read(4))
 
 proc toAddress(r: var EthAddress, x: openArray[byte]) {.inline.} =
   r[0..19] = x[0..19]
@@ -210,7 +209,7 @@ proc extensionNode(t: var TreeBuilder, depth: int): NodeKey =
 
 proc accountNode(t: var TreeBuilder, depth: int): NodeKey =
   assert(depth < 65)
-  let len = t.readU32()
+  let len = t.readU32().int
   result = toNodeKey(t.read(len))
 
   when defined(debugDepth):
diff --git a/stateless/witness_from_tree.nim b/stateless/witness_from_tree.nim
index 672498d97..f117c3f3d 100644
--- a/stateless/witness_from_tree.nim
+++ b/stateless/witness_from_tree.nim
@@ -39,6 +39,9 @@ proc rlpListToBitmask(r: var Rlp): uint =
     inc i
   r.position = 0
 
+proc writeU32(wb: var WitnessBuilder, x: uint32) =
+  wb.output.append(toBytesBE(x))
+
 proc writeNibbles(wb: var WitnessBuilder; n: NibblesSeq) =
   let nibblesLen = n.len
   let numBytes = nibblesLen div 2 + nibblesLen mod 2
@@ -87,7 +90,7 @@ proc writeBranchNode(wb: var WitnessBuilder, mask: uint, depth: int, node: openA
 proc writeAccountNode(wb: var WitnessBuilder, node: openArray[byte], depth: int) =
   # write type
   wb.output.append(AccountNodeType.byte)
-  wb.output.append(toBytesLe(node.len.uint32))
+  wb.writeU32(node.len.uint32)
   wb.output.append(node)
 
   when defined(debugDepth):