diff --git a/fluffy/eth_data/yaml_eth_types.nim b/fluffy/eth_data/yaml_eth_types.nim
index 196c46f2c..5f4394d6c 100644
--- a/fluffy/eth_data/yaml_eth_types.nim
+++ b/fluffy/eth_data/yaml_eth_types.nim
@@ -7,7 +7,7 @@
 
 {.push raises: [].}
 
-import ssz_serialization/types
+import ssz_serialization/types, stew/byteutils
 
 type
   YamlTestProofBellatrix* = object
@@ -38,6 +38,6 @@ proc fromHex*[n](T: type array[n, Digest], a: array[n, string]): T =
 proc toHex*[n](a: array[n, Digest], T: type array[n, string]): T =
   var res: T
   for i in 0 ..< a.len:
-    res[i] = toHex(a[i].data)
+    res[i] = to0xHex(a[i].data)
 
   res
diff --git a/fluffy/eth_data/yaml_utils.nim b/fluffy/eth_data/yaml_utils.nim
index b3d92554f..78b2949ab 100644
--- a/fluffy/eth_data/yaml_utils.nim
+++ b/fluffy/eth_data/yaml_utils.nim
@@ -41,6 +41,20 @@ proc loadFromYaml*(T: type, file: string): Result[T, string] =
   ok(res)
 
 proc dumpToYaml*[T](value: T, file: string): Result[void, string] =
+  # These are the default options aside from outputVersion which is set to none.
+  const options = PresentationOptions(
+    containers: cMixed,
+    indentationStep: 2,
+    newlines: nlOSDefault,
+    outputVersion: ovNone,
+    maxLineLength: some(80),
+    directivesEnd: deIfNecessary,
+    suppressAttrs: false,
+    quoting: sqUnset,
+    condenseFlow: true,
+    explicitKeys: false,
+  )
+
   let s = newFileStream(file, fmWrite)
   defer:
     try:
@@ -48,7 +62,8 @@ proc dumpToYaml*[T](value: T, file: string): Result[void, string] =
     except Exception as e:
       raiseAssert(e.msg)
   try:
-    dump(value, s)
+    # Dump to yaml, avoiding TAGS and YAML version directives.
+    dump(value, s, tagStyle = tsNone, options = options, handles = @[])
   except YamlPresenterJsonError as e:
     return err(e.msg)
   except YamlSerializationError as e:
diff --git a/fluffy/tools/eth_data_exporter/cl_data_exporter.nim b/fluffy/tools/eth_data_exporter/cl_data_exporter.nim
index e97e64d02..048ae96bc 100644
--- a/fluffy/tools/eth_data_exporter/cl_data_exporter.nim
+++ b/fluffy/tools/eth_data_exporter/cl_data_exporter.nim
@@ -347,11 +347,11 @@ proc exportBeaconBlockProofBellatrix(
 
   let yamlTestProof = YamlTestProofBellatrix(
     execution_block_header:
-      beaconBlock.message.body.execution_payload.block_hash.data.toHex,
+      beaconBlock.message.body.execution_payload.block_hash.data.to0xHex(),
     beacon_block_body_proof: blockProof.beaconBlockBodyProof.toHex(array[8, string]),
-    beacon_block_body_root: blockProof.beaconBlockBodyRoot.data.toHex(),
+    beacon_block_body_root: blockProof.beaconBlockBodyRoot.data.to0xHex(),
     beacon_block_header_proof: blockProof.beaconBlockHeaderProof.toHex(array[3, string]),
-    beacon_block_header_root: blockProof.beaconBlockHeaderRoot.data.toHex(),
+    beacon_block_header_root: blockProof.beaconBlockHeaderRoot.data.to0xHex(),
     historical_roots_proof: blockProof.historicalRootsProof.toHex(array[14, string]),
     slot: blockProof.slot.uint64,
   )
@@ -469,11 +469,11 @@ proc exportBeaconBlockProofCapella(
 
   let yamlTestProof = YamlTestProof(
     execution_block_header:
-      beaconBlock.message.body.execution_payload.block_hash.data.toHex,
+      beaconBlock.message.body.execution_payload.block_hash.data.to0xHex(),
     beacon_block_body_proof: blockProof.beaconBlockBodyProof.toHex(array[8, string]),
-    beacon_block_body_root: blockProof.beaconBlockBodyRoot.data.toHex(),
+    beacon_block_body_root: blockProof.beaconBlockBodyRoot.data.to0xHex(),
     beacon_block_header_proof: blockProof.beaconBlockHeaderProof.toHex(array[3, string]),
-    beacon_block_header_root: blockProof.beaconBlockHeaderRoot.data.toHex(),
+    beacon_block_header_root: blockProof.beaconBlockHeaderRoot.data.to0xHex(),
     historical_summaries_proof:
       blockProof.historicalSummariesProof.toHex(array[13, string]),
     slot: blockProof.slot.uint64,