From 5e0ee73b958becaed02d7252f8b4905c862347dc Mon Sep 17 00:00:00 2001
From: Rachel Franks <nfranks@protonmail.com>
Date: Fri, 22 Jul 2022 14:48:57 -0500
Subject: [PATCH] fix oldstyle bitflip

---
 arbstate/inbox.go      | 3 ++-
 das/dastree/dastree.go | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arbstate/inbox.go b/arbstate/inbox.go
index 14faeea191..6adb84c58d 100644
--- a/arbstate/inbox.go
+++ b/arbstate/inbox.go
@@ -213,8 +213,9 @@ func RecoverPayloadFromDasBatch(
 
 	if preimages != nil {
 		if version == 0 {
+			treeLeaf := dastree.FlatHashToTreeLeaf(dataHash)
 			preimages[dataHash] = payload
-			preimages[dastree.FlatHashToTreeHash(dataHash)] = dastree.FlatHashToTreeLeaf(dataHash)
+			preimages[crypto.Keccak256Hash(treeLeaf)] = treeLeaf
 		} else {
 			dastree.RecordHash(recordPreimage, payload)
 		}
diff --git a/das/dastree/dastree.go b/das/dastree/dastree.go
index 9803d45a9f..d23eb230b2 100644
--- a/das/dastree/dastree.go
+++ b/das/dastree/dastree.go
@@ -101,7 +101,7 @@ func HashBytes(preimage ...[]byte) []byte {
 func FlatHashToTreeHash(flat bytes32) bytes32 {
 	// Forms a degenerate dastree that's just a single leaf
 	// note: the inner preimage may be larger than the 64 kB standard
-	return arbmath.FlipBit(crypto.Keccak256Hash(append([]byte{LeafByte}, flat[:]...)), 0)
+	return arbmath.FlipBit(crypto.Keccak256Hash(FlatHashToTreeLeaf(flat)), 0)
 }
 
 func FlatHashToTreeLeaf(flat bytes32) []byte {