From 0f6dd8cedd19ad49626b05b8af57ca5ffec12e90 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1s=20Gr=C3=BCner?=
 <47506558+MegaRedHand@users.noreply.github.com>
Date: Fri, 23 Oct 2026 19:40:42 -0300
Subject: [PATCH] chore(beacon): refresh Sepolia's config from eth-clients

The built-in Sepolia config is eth-clients' file byte for byte, and two
upstream changes since the copy had not been picked up: the Glamsterdam
gas limit schedule (eth-clients/sepolia#130) and the merge-era
TERMINAL_BLOCK_HASH override (eth-clients/sepolia#120).

Neither changes what the node does. GAS_LIMIT_SCHEDULE is reported as an
ignored key, and TERMINAL_BLOCK_HASH only judges the merge transition
block, which Sepolia passed in 2022. What does change is that
/eth/v1/config/spec now reports Sepolia's published override instead of
the zero hash.

first_config_difference already leaves the transition keys out, so a
Sepolia directory written before this still resumes. Its comment claimed
every shipped network leaves them at their defaults, which Sepolia no
longer does; it now says why they are left out regardless.
---
 bin/ethlambda/assets/sepolia/config.yaml | 11 +++++++++--
 bin/ethlambda/src/main.rs                |  9 ++++++---
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/bin/ethlambda/assets/sepolia/config.yaml b/bin/ethlambda/assets/sepolia/config.yaml
index e6c17a836..bf938430a 100644
--- a/bin/ethlambda/assets/sepolia/config.yaml
+++ b/bin/ethlambda/assets/sepolia/config.yaml
@@ -25,8 +25,8 @@ ALTAIR_FORK_EPOCH: 50
 BELLATRIX_FORK_VERSION: 0x90000071
 BELLATRIX_FORK_EPOCH: 100
 TERMINAL_TOTAL_DIFFICULTY: 17000000000000000
-TERMINAL_BLOCK_HASH: 0x0000000000000000000000000000000000000000000000000000000000000000
-TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH: 18446744073709551615
+TERMINAL_BLOCK_HASH: 0xd07cce9785d39c0dd2409b7d8e69d6bff26a69a0fa5308ac781c63ffe2a37bc1
+TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH: 3599
 
 # Capella
 CAPELLA_FORK_VERSION: 0x90000072
@@ -216,3 +216,10 @@ BLOB_SCHEDULE:
     MAX_BLOBS_PER_BLOCK: 15
   - EPOCH: 275712
     MAX_BLOBS_PER_BLOCK: 21
+
+# Gas limit scheduling
+# ---------------------------------------------------------------
+
+GAS_LIMIT_SCHEDULE:
+  - EPOCH: 353024
+    GAS_LIMIT: 200000000
diff --git a/bin/ethlambda/src/main.rs b/bin/ethlambda/src/main.rs
index ad6ac7104..6dc69b096 100644
--- a/bin/ethlambda/src/main.rs
+++ b/bin/ethlambda/src/main.rs
@@ -1592,9 +1592,12 @@ fn first_config_difference(
         reorg_parent_weight_threshold: _,
         reorg_max_epochs_since_finalization: _,
 
-        // Transition (bellatrix): mainnet crossed this in 2022 and every
-        // shipped network leaves it at its default; not worth chain-identity
-        // treatment for the same reason the fork-choice group above is not.
+        // Transition (bellatrix): these only judge the merge transition block
+        // (`validate_merge_block`), and every shipped network is past its
+        // merge. Sepolia's file does set the `TERMINAL_BLOCK_HASH` override
+        // its merge used, but no block a node imports today is checked
+        // against it. Not worth chain-identity treatment for the same reason
+        // the fork-choice group above is not.
         terminal_total_difficulty: _,
         terminal_block_hash: _,
         terminal_block_hash_activation_epoch: _,