Schedule Fusaka on Ethereum mainnet (#17734)

on December 3, 2025, 09:49:11pm UTC
BPO1 December 9, 2025, 02:21:11pm UTC
BPO2 January 7, 2026, 01:01:11am UTC

See https://notes.ethereum.org/@bbusa/fusaka-bpo-timeline,
ethereum/consensus-specs#4689 and
eth-clients/mainnet#11.

`DefaultOsakaBlobConfig` was removed because it's the same as
`DefaultPragueBlobConfig`, so there's no need to set it explicitly.

Author: yperbasis

cl/clparams/config.go

@@ -866,7 +866,7 @@ var MainnetBeaconConfig BeaconChainConfig = BeaconChainConfig{
 	ElectraForkVersion:   0x05000000,
 	ElectraForkEpoch:     364032,
 	FuluForkVersion:      0x06000000,
-	FuluForkEpoch:        math.MaxUint64,
+	FuluForkEpoch:        411392,
 
 	// New values introduced in Altair hard fork 1.
 	// Participation flag indices.
@@ -958,7 +958,10 @@ var MainnetBeaconConfig BeaconChainConfig = BeaconChainConfig{
 	// Fulu
 	ValidatorCustodyRequirement:      8,
 	BalancePerAdditionalCustodyGroup: 32_000_000_000,
-	BlobSchedule:                     []BlobParameters{},
+	BlobSchedule: []BlobParameters{
+		{412672, 15},
+		{419072, 21},
+	},
 }
 
 func mainnetConfig() BeaconChainConfig {
@@ -1117,6 +1120,7 @@ func gnosisConfig() BeaconChainConfig {
 	cfg.MaxPerEpochActivationExitChurnLimit = 64_000_000_000
 	cfg.MaxRequestBlobSidecarsElectra = 256
 	cfg.MaxPendingPartialsPerWithdrawalsSweep = 6
+	cfg.BlobSchedule = []BlobParameters{}
 	cfg.InitializeForkSchedule()
 	return cfg
 }
@@ -1161,6 +1165,7 @@ func chiadoConfig() BeaconChainConfig {
 	cfg.MaxPerEpochActivationChurnLimit = 2
 	cfg.MaxPerEpochActivationExitChurnLimit = 64_000_000_000
 	cfg.MaxRequestBlobSidecarsElectra = 256
+	cfg.BlobSchedule = []BlobParameters{}
 	cfg.InitializeForkSchedule()
 	return cfg
 }

cl/utils/eth_clock/ethereum_clock_test.go

@@ -37,7 +37,7 @@ func TestGetForkDigests(t *testing.T) {
 	clock := NewEthereumClock(0, common.Hash{}, &clparams.MainnetBeaconConfig)
 	currDigest, err := clock.CurrentForkDigest()
 	require.NoError(t, err)
-	require.Equal(t, common.Bytes4{0xc8, 0xb9, 0xe6, 0xac}, currDigest)
+	require.Equal(t, common.Bytes4{0x0b, 0x15, 0x44, 0xdc}, currDigest)
 	nextDigest, err := clock.NextForkDigest()
 	require.NoError(t, err)
 	lastFork, err := clock.LastFork()

execution/chain/chain_config.go

@@ -380,9 +380,6 @@ func (c *Config) GetBlobConfig(time uint64) *params.BlobConfig {
 		if c.PragueTime != nil {
 			c.parsedBlobSchedule[c.PragueTime.Uint64()] = &params.DefaultPragueBlobConfig
 		}
-		if c.OsakaTime != nil {
-			c.parsedBlobSchedule[c.OsakaTime.Uint64()] = &params.DefaultOsakaBlobConfig
-		}
 
 		// Override with supplied values
 		val, ok := c.BlobSchedule["cancun"]

execution/chain/params/protocol.go

@@ -255,9 +255,3 @@ var DefaultPragueBlobConfig = BlobConfig{
 	Max:                   9,
 	BaseFeeUpdateFraction: 5007716,
 }
-
-var DefaultOsakaBlobConfig = BlobConfig{
-	Target:                6,
-	Max:                   9,
-	BaseFeeUpdateFraction: 5007716,
-}

execution/chain/spec/chainspecs/mainnet.json

@@ -21,6 +21,9 @@
   "shanghaiTime": 1681338455,
   "cancunTime": 1710338135,
   "pragueTime": 1746612311,
+  "osakaTime": 1764798551,
+  "bpo1Time": 1765290071,
+  "bpo2Time": 1767747671,
   "blobSchedule": {
     "cancun": {
       "target": 3,
@@ -31,6 +34,16 @@
       "target": 6,
       "max": 9,
       "baseFeeUpdateFraction": 5007716
+    },
+    "bpo1": {
+      "target": 10,
+      "max": 15,
+      "baseFeeUpdateFraction": 8346193
+    },
+    "bpo2": {
+      "target": 14,
+      "max": 21,
+      "baseFeeUpdateFraction": 11684671
     }
   },
   "depositContractAddress": "0x00000000219ab540356cBB839Cbe05303d7705Fa",

p2p/forkid/forkid_test.go

@@ -77,9 +77,9 @@ func TestCreation(t *testing.T) {
 				{17034870, 1681338479, ID{Hash: ChecksumToBytes(0xdce96c2d), Activation: 1681338455, Next: 1710338135}}, // First Shanghai block
 				{19426586, 1710338123, ID{Hash: ChecksumToBytes(0xdce96c2d), Activation: 1681338455, Next: 1710338135}}, // Last Shanghai block
 				{19426587, 1710338135, ID{Hash: ChecksumToBytes(0x9f3d2254), Activation: 1710338135, Next: 1746612311}}, // First Cancun block
-				{22432453, 1746612299, ID{Hash: ChecksumToBytes(0x9f3d2254), Activation: 1710338135, Next: 1746612311}}, // Last Cancun block (approx.)
-				{22432454, 1746612311, ID{Hash: ChecksumToBytes(0xc376cf8b), Activation: 1746612311, Next: 0}},          // First Prague block (approx.)
-				{30000000, 1900000000, ID{Hash: ChecksumToBytes(0xc376cf8b), Activation: 1746612311, Next: 0}},          // Future Prague block (mock)
+				{22431083, 1746612299, ID{Hash: ChecksumToBytes(0x9f3d2254), Activation: 1710338135, Next: 1746612311}}, // Last Cancun block
+				{22431084, 1746612311, ID{Hash: ChecksumToBytes(0xc376cf8b), Activation: 1746612311, Next: 1764798551}}, // First Prague block
+				{30000000, 1900000000, ID{Hash: ChecksumToBytes(0x07c9462e), Activation: 1767747671, Next: 0}},          // Future block (mock)
 			},
 		},
 		{