From cd0ddad4bba2e0d1a7451343ed18661fc563b2c8 Mon Sep 17 00:00:00 2001
From: Guillaume Ballet <3272758+gballet@users.noreply.github.com>
Date: Tue, 28 Nov 2023 11:15:46 +0100
Subject: [PATCH 1/2] fix: support a verkle pre-tree at the conversion block

---
 consensus/beacon/consensus.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/consensus/beacon/consensus.go b/consensus/beacon/consensus.go
index 2ca701c42f56..390e56013cbb 100644
--- a/consensus/beacon/consensus.go
+++ b/consensus/beacon/consensus.go
@@ -423,7 +423,15 @@ func (beacon *Beacon) FinalizeAndAssemble(chain consensus.ChainHeaderReader, hea
 			vtrpost = post.Overlay()
 			okpost = true
 		default:
-			panic("invalid tree type")
+			// This should only happen for the first block of the
+			// conversion, when the previous tree is a merkle tree.
+			//  Logically, the "previous" verkle tree is an empty tree.
+			okpre = true
+			vtrpre = trie.NewVerkleTrie(verkle.New(), state.Database().TrieDB(), utils.NewPointCache(), false)
+			post := state.GetTrie().(*trie.TransitionTrie)
+			vtrpost = post.Overlay()
+			okpost = true
+
 		}
 		if okpre && okpost {
 			if len(keys) > 0 {

From cc61f5c3f92472bbb2479d3c5129f6b1a18f3e01 Mon Sep 17 00:00:00 2001
From: Guillaume Ballet <3272758+gballet@users.noreply.github.com>
Date: Mon, 29 Jan 2024 09:49:51 +0100
Subject: [PATCH 2/2] make linter happy

---
 consensus/beacon/consensus.go | 1 -
 1 file changed, 1 deletion(-)

diff --git a/consensus/beacon/consensus.go b/consensus/beacon/consensus.go
index 390e56013cbb..c2181fca9bda 100644
--- a/consensus/beacon/consensus.go
+++ b/consensus/beacon/consensus.go
@@ -431,7 +431,6 @@ func (beacon *Beacon) FinalizeAndAssemble(chain consensus.ChainHeaderReader, hea
 			post := state.GetTrie().(*trie.TransitionTrie)
 			vtrpost = post.Overlay()
 			okpost = true
-
 		}
 		if okpre && okpost {
 			if len(keys) > 0 {