From 1a7e0397bbf5faf711cdf32687df34a5bcb9032c Mon Sep 17 00:00:00 2001
From: healthykim <bsbs8645@snu.ac.kr>
Date: Thu, 14 May 2026 19:15:48 +0200
Subject: [PATCH] core, eth: new engine api spec

---
 core/types/custody_bitmap.go | 32 ++++++++------------------------
 eth/catalyst/api.go          |  9 ++++-----
 2 files changed, 12 insertions(+), 29 deletions(-)

diff --git a/core/types/custody_bitmap.go b/core/types/custody_bitmap.go
index d3624bb914..74585cdc42 100644
--- a/core/types/custody_bitmap.go
+++ b/core/types/custody_bitmap.go
@@ -18,47 +18,31 @@ package types
 
 import (
 	"fmt"
-	"math/big"
 	"math/bits"
 	"math/rand"
 
+	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 )
 
 // CustodyBitmap is a bitmap to represent which custody index to store (little endian).
-// It is serialized as a hex-encoded uint128 quantity (e.g. "0x89") for JSON-RPC.
 type CustodyBitmap [16]byte
 
 // MarshalText implements encoding.TextMarshaler.
-// Encodes the bitmap as a hex-encoded uint128 quantity.
 func (b CustodyBitmap) MarshalText() ([]byte, error) {
-	var be [16]byte
-	for i := range b {
-		be[15-i] = b[i]
-	}
-	v := new(big.Int).SetBytes(be[:])
-	return []byte("0x" + v.Text(16)), nil
+	return []byte(hexutil.Encode(b[:])), nil
 }
 
 // UnmarshalText implements encoding.TextUnmarshaler.
-// Parses a hex-encoded uint128 quantity into the bitmap.
 func (b *CustodyBitmap) UnmarshalText(input []byte) error {
-	s := string(input)
-	if len(s) < 2 || (s[:2] != "0x" && s[:2] != "0X") {
-		return fmt.Errorf("custody bitmap: missing 0x prefix")
+	decoded, err := hexutil.Decode(string(input))
+	if err != nil {
+		return fmt.Errorf("custody bitmap: %v", err)
 	}
-	v, ok := new(big.Int).SetString(s[2:], 16)
-	if !ok {
-		return fmt.Errorf("custody bitmap: invalid hex %q", s)
-	}
-	if v.BitLen() > 128 {
-		return fmt.Errorf("custody bitmap: value exceeds 128 bits")
-	}
-	*b = CustodyBitmap{}
-	beBytes := v.Bytes() // big-endian
-	for i, byt := range beBytes {
-		b[len(beBytes)-1-i] = byt
+	if len(decoded) != len(b) {
+		return fmt.Errorf("custody bitmap: invalid length %d, want %d", len(decoded), len(b))
 	}
+	copy(b[:], decoded)
 	return nil
 }
 
diff --git a/eth/catalyst/api.go b/eth/catalyst/api.go
index b980920493..ebe0b880aa 100644
--- a/eth/catalyst/api.go
+++ b/eth/catalyst/api.go
@@ -214,7 +214,7 @@ func (api *ConsensusAPI) ForkchoiceUpdatedV3(ctx context.Context, update engine.
 
 // ForkchoiceUpdatedV4 is equivalent to V3 with the addition of slot number
 // in the payload attributes. It supports only PayloadAttributesV4.
-func (api *ConsensusAPI) ForkchoiceUpdatedV4(ctx context.Context, update engine.ForkchoiceStateV1, params *engine.PayloadAttributes) (engine.ForkChoiceResponse, error) {
+func (api *ConsensusAPI) ForkchoiceUpdatedV4(ctx context.Context, update engine.ForkchoiceStateV1, params *engine.PayloadAttributes, custodyColumns *types.CustodyBitmap) (engine.ForkChoiceResponse, error) {
 	if params != nil {
 		switch {
 		case params.Withdrawals == nil:
@@ -227,6 +227,9 @@ func (api *ConsensusAPI) ForkchoiceUpdatedV4(ctx context.Context, update engine.
 			return engine.STATUS_INVALID, unsupportedForkErr("fcuV4 must only be called for amsterdam payloads")
 		}
 	}
+	if custodyColumns != nil {
+		api.eth.BlobFetcher().UpdateCustody(*custodyColumns)
+	}
 	// TODO(matt): the spec requires that fcu is applied when called on a valid
 	// hash, even if params are wrong. To do this we need to split up
 	// forkchoiceUpdate into a function that only updates the head and then a
@@ -1218,10 +1221,6 @@ func (api *ConsensusAPI) getBodiesByRange(start, count hexutil.Uint64) ([]*engin
 	return bodies, nil
 }
 
-func (api *ConsensusAPI) BlobCustodyUpdatedV1(indicesBitarray types.CustodyBitmap) {
-	api.eth.BlobFetcher().UpdateCustody(indicesBitarray)
-}
-
 func getBody(block *types.Block) *engine.ExecutionPayloadBody {
 	if block == nil {
 		return nil