Skip to content

Ethereum Mainnet EVM Compatibility Specification

Overview

This document provides a comprehensive analysis of the Ethereum Improvement Proposals (EIPs), VM opcodes, and protocol features required for Fukuii to claim full Ethereum mainnet execution client compatibility. Fukuii was originally designed as an Ethereum Classic client, and this specification identifies the gaps and requirements for Ethereum mainnet compatibility.

Table of Contents

  1. Current Implementation Status
  2. Implemented EIPs
  3. Ethereum Mainnet Fork History
  4. Missing EIPs for Full Compatibility
  5. Opcode Implementation Status
  6. Precompiled Contracts
  7. Consensus and Protocol Differences
  8. Testing and Validation
  9. Implementation Roadmap

Current Implementation Status

Summary

Category Implemented Partial Missing
Pre-Merge EIPs 30+ 0 3+
Post-Merge EIPs 0 0 10+
Pectra/Fusaka EIPs 4 1 4
Opcodes 146/148 0 2
Precompiled Contracts 10/19 9 0

Compatibility Level

  • ETC Olympia (ECIP-1111/1112/1121): ✅ Full compatibility — EIP-1559, EVM modernization, new precompiles
  • ETC Spiral (≈ Shanghai equivalent): ✅ Full compatibility
  • Ethereum Berlin: ✅ Full compatibility
  • Ethereum London: ✅ EIP-1559 + BASEFEE implemented (via Olympia)
  • Ethereum Paris (The Merge): ❌ Not implemented (PoS not applicable to ETC)
  • Ethereum Shanghai: ⚠️ Partial (PUSH0, COINBASE warm — yes; beacon withdrawals — N/A)
  • Ethereum Cancun (Dencun): ⚠️ Partial (TLOAD/TSTORE, MCOPY, EIP-6780 — yes; blobs — no)
  • Ethereum Prague (Pectra/Fusaka): ⚠️ Partial (EIP-7702, EIP-2935, EIP-2537 stubs, EIP-2565 — yes; beacon features — N/A)

Implemented EIPs

Frontier Era (Block 0)

EIP Title Status Notes
N/A Initial EVM opcodes ✅ Implemented 130+ base opcodes

Homestead (Block 1,150,000)

EIP Title Status Notes
EIP-2 Homestead Hard-fork Changes ✅ Implemented Contract creation, tx validation
EIP-7 DELEGATECALL ✅ Implemented Opcode 0xF4
EIP-8 devp2p Forward Compatibility ✅ Implemented Network protocol

Tangerine Whistle (Block 2,463,000)

EIP Title Status Notes
EIP-150 Gas cost changes for IO-heavy operations ✅ Implemented EXTCODE*, CALL*, SLOAD updates

Spurious Dragon (Block 2,675,000)

EIP Title Status Notes
EIP-155 Simple replay attack protection ✅ Implemented Chain ID in tx signature
EIP-160 EXP cost increase ✅ Implemented G_expbyte = 50
EIP-161 State trie clearing ✅ Implemented noEmptyAccounts flag
EIP-170 Contract code size limit ✅ Implemented MAX_CODE_SIZE = 24576

Byzantium (Block 4,370,000)

EIP Title Status Notes
EIP-100 Difficulty adjustment ✅ Implemented Uncle inclusion adjustment
EIP-140 REVERT instruction ✅ Implemented Opcode 0xFD
EIP-196 BN128 addition and multiplication ✅ Implemented Precompiles at 0x06, 0x07
EIP-197 BN128 pairing check ✅ Implemented Precompile at 0x08
EIP-198 Big integer modular exponentiation ✅ Implemented Precompile at 0x05
EIP-211 RETURNDATASIZE and RETURNDATACOPY ✅ Implemented Opcodes 0x3D, 0x3E
EIP-214 STATICCALL ✅ Implemented Opcode 0xFA
EIP-649 Difficulty bomb delay ✅ Implemented Block reward reduction
EIP-658 Transaction status in receipts ✅ Implemented Status field in receipts

Constantinople/Petersburg (Block 7,280,000)

EIP Title Status Notes
EIP-145 Bitwise shifting ✅ Implemented SHL, SHR, SAR opcodes
EIP-1014 Skinny CREATE2 ✅ Implemented Opcode 0xF5
EIP-1052 EXTCODEHASH ✅ Implemented Opcode 0x3F
EIP-1234 Constantinople bomb delay ✅ Implemented Block reward = 2 ETH
EIP-1283 Net gas metering for SSTORE ✅ Implemented Constantinople only

Istanbul (Block 9,069,000)

EIP Title Status Notes
EIP-152 Blake2b F compression ✅ Implemented Precompile at 0x09
EIP-1108 BN128 gas cost reduction ✅ Implemented Reduced gas for BN128 ops
EIP-1344 ChainID opcode ✅ Implemented Opcode 0x46
EIP-1884 Opcode repricing ✅ Implemented SLOAD, BALANCE, EXTCODEHASH
EIP-2028 Calldata gas reduction ✅ Implemented G_txdatanonzero = 16
EIP-2200 SSTORE gas changes (net metering) ✅ Implemented Combined with EIP-1283

Berlin (Block 12,244,000)

EIP Title Status Notes
EIP-2565 ModExp gas cost ✅ Implemented Repriced modular exponentiation
EIP-2718 Typed Transaction Envelope ✅ Implemented Types 0 (legacy), 1 (access list), 2 (EIP-1559), 4 (EIP-7702)
EIP-2929 Gas cost increases for state access ✅ Implemented Cold/warm access tracking
EIP-2930 Optional access lists ✅ Implemented Type-1 access list transactions

London (Block 12,965,000)

EIP Title Status Notes
EIP-1559 Fee market change ✅ Implemented Via ETC Olympia (ECIP-1111) — baseFee, Type-2 transactions
EIP-3198 BASEFEE opcode ✅ Implemented Via ETC Olympia (ECIP-1112) — Opcode 0x48
EIP-3529 Reduce refunds ✅ Implemented SELFDESTRUCT refund = 0
EIP-3541 Reject new contracts starting with 0xEF ✅ Implemented EOF preparation

Paris/The Merge (Block 15,537,394)

EIP Title Status Notes
EIP-3675 Upgrade consensus to Proof-of-Stake ❌ Missing Beacon chain integration
EIP-4399 DIFFICULTY → PREVRANDAO ❌ Missing Opcode behavior change

Shanghai (Block 17,034,870)

EIP Title Status Notes
EIP-3651 Warm COINBASE ✅ Implemented Coinbase in warm addresses
EIP-3855 PUSH0 instruction ✅ Implemented Opcode 0x5F
EIP-3860 Limit and meter initcode ✅ Implemented MAX_INITCODE_SIZE
EIP-4895 Beacon chain push withdrawals ❌ Missing Validator withdrawals
EIP-6049 Deprecate SELFDESTRUCT ✅ Implemented Informational only

Cancun (Block 19,426,587)

EIP Title Status Notes
EIP-1153 Transient storage opcodes ✅ Implemented Via ETC Olympia (ECIP-1112) — TLOAD, TSTORE
EIP-4788 Beacon block root in EVM ❌ N/A Beacon chain not applicable to ETC (PoW)
EIP-4844 Shard Blob Transactions ❌ N/A Proto-danksharding not in ETC scope
EIP-5656 MCOPY instruction ✅ Implemented Via ETC Olympia (ECIP-1112) — Opcode 0x5E
EIP-6780 SELFDESTRUCT changes ✅ Implemented Via ETC Olympia (ECIP-1112) — same-transaction only
EIP-7516 BLOBBASEFEE opcode ❌ N/A Blob transactions not in ETC scope

Prague/Pectra (Execution: Prague, Consensus: Fusaka - Activated May 7, 2025)

Note: EIP-7251 and EIP-7549 appear in both sections as they affect both execution and consensus layers.

EIP Title Status Notes
Execution Layer EIPs
EIP-2537 BLS12-381 precompiles ⚠️ Stubs Via ETC Olympia (ECIP-1112) — gas-consuming stubs, full crypto TBD
EIP-2935 Serve historical block hashes from state ✅ Implemented Via ETC Olympia (ECIP-1112) — system contract, 8191 history window
EIP-6110 Supply validator deposits on chain ❌ N/A Validator deposits not applicable to ETC (PoW)
EIP-7002 Execution layer triggerable exits ❌ N/A Validator exits not applicable to ETC (PoW)
EIP-7251 Increase MAX_EFFECTIVE_BALANCE ❌ N/A Validator economics not applicable to ETC (PoW)
EIP-7549 Move committee index outside Attestation ❌ N/A Consensus layer not applicable to ETC (PoW)
EIP-7685 General purpose execution layer requests ❌ N/A EL request framework not applicable to ETC (PoW)
EIP-7702 Set EOA account code for one transaction ✅ Implemented Via ETC Olympia (ECIP-1121) — Type-4 transactions
Consensus Layer EIPs (Fusaka)
EIP-7251 Max effective balance (Consensus) ❌ Missing Validator consolidation support
EIP-7549 Committee index optimization ❌ Missing Attestation efficiency
EIP-7594 PeerDAS (Peer Data Availability Sampling) ❌ Missing Data availability layer

Ethereum Mainnet Fork History

Block 0          │ Frontier
Block 200,000    │ Frontier Thawing
Block 1,150,000  │ Homestead
Block 1,920,000  │ DAO Fork (ETC split)
Block 2,463,000  │ Tangerine Whistle
Block 2,675,000  │ Spurious Dragon
Block 4,370,000  │ Byzantium
Block 7,280,000  │ Constantinople/Petersburg
Block 9,069,000  │ Istanbul
Block 9,200,000  │ Muir Glacier
Block 12,244,000 │ Berlin
Block 12,965,000 │ London          ← EIP-1559 (base fee)
Block 13,773,000 │ Arrow Glacier
Block 15,050,000 │ Gray Glacier
Block 15,537,394 │ Paris (The Merge) ← PoS transition
Block 17,034,870 │ Shanghai        ← Withdrawals
Block 19,426,587 │ Cancun (Dencun) ← Proto-danksharding
Slot 10388992    │ Prague (Pectra/Fusaka) ← Account abstraction, MaxEB, EL requests
(May 7, 2025)    │ (Execution: Prague, Consensus: Fusaka)

Missing EIPs for Full Compatibility

Critical Path (Required for Basic Compatibility)

1. EIP-1559: Fee Market Change ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1111). BaseFee header field, Type-2 transactions, base fee adjustment algorithm. On ETC, base fee is redirected to treasury (not burned).

2. EIP-3198: BASEFEE Opcode ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1112). Opcode 0x48 returns current block baseFee.

3. EIP-4399: Supplant DIFFICULTY with PREVRANDAO

Priority: 🔴 Critical (post-Merge)
Complexity: Low
Impact: DIFFICULTY opcode behavior

Changes: - After The Merge, DIFFICULTY (0x44) returns the beacon chain RANDAO value - Rename to PREVRANDAO semantically - Update block header to include prevRandao field

4. EIP-3675: Upgrade Consensus to Proof-of-Stake

Priority: 🔴 Critical (for mainnet sync)
Complexity: Very High
Impact: Consensus, block production

Requirements: - Engine API implementation (JSON-RPC for consensus/execution layer communication) - Block building without PoW - Beacon chain integration - Fork choice rule changes - Terminal Total Difficulty (TTD) handling

High Priority (Required for Modern Features)

5. EIP-4895: Beacon Chain Push Withdrawals

Priority: 🟠 High
Complexity: Medium
Impact: Block processing

Requirements: - Add withdrawals field to block body - Process withdrawals as balance credits - Withdrawal index tracking

6. EIP-1153: Transient Storage Opcodes ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1112). TLOAD (0x5C) and TSTORE (0x5D) opcodes. Per-transaction, per-address transient storage cleared at end of transaction. 100 gas per operation.

7. EIP-5656: MCOPY Instruction ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1112). MCOPY (0x5E) memory copy opcode.

New Opcode: | Opcode | Name | Description | |--------|------|-------------| | 0x5E | MCOPY | Memory copy |

Gas Calculation: 

gas = G_verylow + G_copy * ceil(size / 32) + memory_expansion_cost

8. EIP-6780: SELFDESTRUCT Only in Same Transaction ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1112). Post-Olympia, SELFDESTRUCT only deletes the account if called in the same transaction as contract creation. Otherwise, only transfers balance.

Medium Priority (Required for Complete Compliance)

9. EIP-4844: Shard Blob Transactions

Priority: 🟡 Medium
Complexity: Very High
Impact: Transaction types, data availability

Requirements: - Type 3 (blob) transactions - KZG commitments and proofs - Blob data handling - Data availability sampling (future)

New Components: - blob_versioned_hashes in transactions - excess_blob_gas and blob_gas_used in headers - Precompile at 0x0A (point evaluation)

10. EIP-7516: BLOBBASEFEE Opcode

Priority: 🟡 Medium (depends on EIP-4844)
Complexity: Low
Impact: EVM opcode

New Opcode: | Opcode | Name | Description | |--------|------|-------------| | 0x4A | BLOBBASEFEE | Get blob base fee |

11. EIP-4788: Beacon Block Root in EVM

Priority: 🟡 Medium
Complexity: Medium
Impact: System contract

Requirements: - System contract at address 0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02 - Stores beacon block roots - Ring buffer of 8191 entries

Lower Priority (Future Enhancements)

12. EIP-2537: BLS12-381 Curve Operations ⚠️ STUBS ONLY

Registered as gas-consuming stubs via ETC Olympia (ECIP-1112). Full crypto implementation TBD. Priority: 🟡 Medium (stubs deployed, full implementation deferred) Complexity: High Impact: Precompiled contracts

New Precompiles: | Address | Name | Description | |---------|------|-------------| | 0x0B | BLS12_G1ADD | G1 point addition | | 0x0C | BLS12_G1MUL | G1 point multiplication | | 0x0D | BLS12_G1MSM | G1 multi-scalar multiplication | | 0x0E | BLS12_G2ADD | G2 point addition | | 0x0F | BLS12_G2MUL | G2 point multiplication | | 0x10 | BLS12_G2MSM | G2 multi-scalar multiplication | | 0x11 | BLS12_PAIRING | Pairing check | | 0x12 | BLS12_MAP_FP_TO_G1 | Hash to G1 | | 0x13 | BLS12_MAP_FP2_TO_G2 | Hash to G2 |

Notes: - Required for efficient BLS signature verification in EVM - Critical for Ethereum consensus layer integration - Activated as part of Pectra/Fusaka (May 7, 2025)

Prague/Pectra (Fusaka) EIPs - Activated May 7, 2025

13. EIP-2935: Serve Historical Block Hashes from State ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1112). System contract at 0x...002935 stores block hashes in a ring buffer (8191 history window). Deployed at fork activation.

14. EIP-6110: Supply Validator Deposits on Chain

Priority: 🔴 Critical (Execution-Consensus Integration)
Complexity: High
Impact: Deposit contract, block structure

Requirements: - Process deposit events from deposit contract in execution layer - Add deposits field to execution payload - Remove reliance on consensus layer for deposit processing - Maximum 8192 deposits per block

Deposit Contract: 0x00000000219ab540356cBB839Cbe05303d7705Fa

Implementation Notes: - Deposits are extracted from logs in execution layer - Improves execution-consensus layer separation - Part of Engine API v4

15. EIP-7002: Execution Layer Triggerable Exits

Priority: 🟠 High
Complexity: Medium
Impact: Validator exits, block structure

Requirements: - System contract at 0x00431D736Ab7fA9C4d1B0e70c1E2B8a0e79e3C4e - Allows validators to trigger exits from execution layer - Add exits field to execution payload - Maximum 16 exits per block

Exit Request Structure: 

case class ExitRequest(
  validatorPubkey: ByteString,  // 48 bytes
  amount: BigInt                 // uint64 value (represented as BigInt in Scala)
)

16. EIP-7251: Increase MAX_EFFECTIVE_BALANCE

Priority: 🟡 Medium (Consensus Layer)
Complexity: Medium
Impact: Validator economics, consolidations

Changes: - Increases MAX_EFFECTIVE_BALANCE from 32 ETH to 2048 ETH - Allows validator consolidation - Reduces beacon chain state size - Execution layer needs to support consolidation requests

Impact on Execution Layer: - Must support validator consolidation requests - Part of general request framework (EIP-7685)

17. EIP-7549: Move Committee Index Outside Attestation

Priority: 🟢 Lower (Consensus Layer)
Complexity: Low
Impact: Attestation structure

Notes: - Primarily consensus layer change - Improves attestation efficiency - No direct execution layer impact - Minimal execution client changes required

18. EIP-7685: General Purpose Execution Layer Requests

Priority: 🔴 Critical
Complexity: Medium
Impact: Block structure, Engine API

Requirements: - Framework for execution layer to consensus layer requests - Add requests field to execution payload - Support multiple request types (deposits, exits, consolidations)

Request Types: | Type ID | Name | EIP | |---------|------|-----| | 0x00 | Deposit | EIP-6110 | | 0x01 | Exit | EIP-7002 | | 0x02 | Consolidation | EIP-7251 |

Implementation: 

case class ExecutionPayload(
  // ... existing fields ...
  requests: Seq[Request]  // New field
)

sealed trait Request {
  def requestType: Byte
}

19. EIP-7702: Set EOA Account Code for One Transaction ✅ IMPLEMENTED

Implemented via ETC Olympia (ECIP-1121). Type-4 transactions with authorization lists. Enables account abstraction, batched transactions, gas sponsorship.

20. EIP-7594: PeerDAS (Peer Data Availability Sampling)

Priority: 🟢 Lower (Consensus Layer)
Complexity: Very High
Impact: Data availability, networking

Notes: - Primarily consensus layer feature - Improves data availability sampling - Reduces bandwidth requirements for validators - Minimal direct execution client impact - Enables more efficient blob handling

Opcode Implementation Status

Complete Implementation (142 opcodes)

Arithmetic Operations (0x00-0x0B)

Opcode Name Gas Status
0x00 STOP 0 ✅
0x01 ADD 3 ✅
0x02 MUL 5 ✅
0x03 SUB 3 ✅
0x04 DIV 5 ✅
0x05 SDIV 5 ✅
0x06 MOD 5 ✅
0x07 SMOD 5 ✅
0x08 ADDMOD 8 ✅
0x09 MULMOD 8 ✅
0x0A EXP 10* ✅
0x0B SIGNEXTEND 5 ✅

Comparison & Bitwise Logic (0x10-0x1D)

Opcode Name Gas Status
0x10 LT 3 ✅
0x11 GT 3 ✅
0x12 SLT 3 ✅
0x13 SGT 3 ✅
0x14 EQ 3 ✅
0x15 ISZERO 3 ✅
0x16 AND 3 ✅
0x17 OR 3 ✅
0x18 XOR 3 ✅
0x19 NOT 3 ✅
0x1A BYTE 3 ✅
0x1B SHL 3 ✅
0x1C SHR 3 ✅
0x1D SAR 3 ✅

SHA3 (0x20)

Opcode Name Gas Status
0x20 SHA3 30* ✅

Environmental Information (0x30-0x3F)

Opcode Name Gas Status
0x30 ADDRESS 2 ✅
0x31 BALANCE 100-2600* ✅
0x32 ORIGIN 2 ✅
0x33 CALLER 2 ✅
0x34 CALLVALUE 2 ✅
0x35 CALLDATALOAD 3 ✅
0x36 CALLDATASIZE 2 ✅
0x37 CALLDATACOPY 3* ✅
0x38 CODESIZE 2 ✅
0x39 CODECOPY 3* ✅
0x3A GASPRICE 2 ✅
0x3B EXTCODESIZE 100-2600* ✅
0x3C EXTCODECOPY 100-2600* ✅
0x3D RETURNDATASIZE 2 ✅
0x3E RETURNDATACOPY 3* ✅
0x3F EXTCODEHASH 100-2600* ✅

Block Information (0x40-0x48)

Opcode Name Gas Status Notes
0x40 BLOCKHASH 20 ✅
0x41 COINBASE 2 ✅
0x42 TIMESTAMP 2 ✅
0x43 NUMBER 2 ✅
0x44 DIFFICULTY/PREVRANDAO 2 ⚠️ Returns difficulty, not prevRandao
0x45 GASLIMIT 2 ✅
0x46 CHAINID 2 ✅
0x47 SELFBALANCE 5 ✅
0x48 BASEFEE 2 ✅ EIP-3198 via Olympia (ECIP-1112)

Stack, Memory, Storage, Flow Operations (0x50-0x5F)

Opcode Name Gas Status
0x50 POP 2 ✅
0x51 MLOAD 3* ✅
0x52 MSTORE 3* ✅
0x53 MSTORE8 3* ✅
0x54 SLOAD 100-2100* ✅
0x55 SSTORE 100-20000* ✅
0x56 JUMP 8 ✅
0x57 JUMPI 10 ✅
0x58 PC 2 ✅
0x59 MSIZE 2 ✅
0x5A GAS 2 ✅
0x5B JUMPDEST 1 ✅
0x5C TLOAD 100 ✅
0x5D TSTORE 100 ✅
0x5E MCOPY 3* ✅
0x5F PUSH0 2 ✅

Push Operations (0x60-0x7F)

All PUSH1-PUSH32 opcodes: ✅ Implemented

Dup Operations (0x80-0x8F)

All DUP1-DUP16 opcodes: ✅ Implemented

Swap Operations (0x90-0x9F)

All SWAP1-SWAP16 opcodes: ✅ Implemented

Log Operations (0xA0-0xA4)

All LOG0-LOG4 opcodes: ✅ Implemented

System Operations (0xF0-0xFF)

Opcode Name Gas Status
0xF0 CREATE 32000* ✅
0xF1 CALL 100-2600* ✅
0xF2 CALLCODE 100-2600* ✅
0xF3 RETURN 0* ✅
0xF4 DELEGATECALL 100-2600* ✅
0xF5 CREATE2 32000* ✅
0xFA STATICCALL 100-2600* ✅
0xFD REVERT 0* ✅
0xFE INVALID all gas ✅
0xFF SELFDESTRUCT 5000* ✅

Missing Opcodes Summary

Opcode Name EIP Priority
0x4A BLOBBASEFEE EIP-7516 ❌ N/A (blob transactions not in ETC scope)

Precompiled Contracts

Implemented Precompiles

Address Name EIP Status
0x01 ECRECOVER Frontier ✅
0x02 SHA256 Frontier ✅
0x03 RIPEMD160 Frontier ✅
0x04 IDENTITY Frontier ✅
0x05 MODEXP EIP-198/2565 ✅
0x06 BN128ADD EIP-196 ✅
0x07 BN128MUL EIP-196 ✅
0x08 BN128PAIRING EIP-197 ✅
0x09 BLAKE2F EIP-152 ✅
0x0100 P256VERIFY EIP-7951 ✅

BLS12-381 Precompiles (Stubs)

Via ETC Olympia (ECIP-1112). Registered as gas-consuming stubs that return failure. Full cryptographic implementation requires a JVM-compatible BLS library (Milagro or Blst JNI bindings).

Address Name EIP Status
0x0B BLS12_G1ADD EIP-2537 ⚠️ Stub
0x0C BLS12_G1MUL EIP-2537 ⚠️ Stub
0x0D BLS12_G1MSM EIP-2537 ⚠️ Stub
0x0E BLS12_G2ADD EIP-2537 ⚠️ Stub
0x0F BLS12_G2MUL EIP-2537 ⚠️ Stub
0x10 BLS12_G2MSM EIP-2537 ⚠️ Stub
0x11 BLS12_PAIRING EIP-2537 ⚠️ Stub
0x12 BLS12_MAP_FP_TO_G1 EIP-2537 ⚠️ Stub
0x13 BLS12_MAP_FP2_TO_G2 EIP-2537 ⚠️ Stub

Missing Precompiles

Address Name EIP Priority
0x0A KZG_POINT_EVALUATION EIP-4844 ❌ N/A (blob transactions not in ETC scope)

Transaction Types

Ethereum has evolved from a single transaction format to multiple typed transactions using the envelope format (EIP-2718). Fukuii supports Type 0 (legacy), Type 1 (access list), Type 2 (EIP-1559 dynamic fee), and Type 4 (EIP-7702 Set Code) transactions via the Olympia hard fork.

Type 0: Legacy Transactions (Pre-EIP-2718)

Status: ✅ Implemented
EIP: N/A (Original format)

Structure: 

rlp([nonce, gasPrice, gasLimit, to, value, data, v, r, s])

Fields: - nonce: Transaction counter for sender - gasPrice: Gas price in wei - gasLimit: Maximum gas allowed - to: Recipient address (or empty for contract creation) - value: ETH amount to transfer - data: Contract data or initialization code - v, r, s: ECDSA signature components

Limitations: - Fixed gas price (no priority fee) - No access lists - No chain ID protection in pre-EIP-155 transactions

Type 1: Access List Transactions (EIP-2930)

Status: ✅ Implemented (Berlin + Olympia) EIP: EIP-2930

Structure: 

0x01 || rlp([chainId, nonce, gasPrice, gasLimit, to, value, data, accessList, signatureYParity, signatureR, signatureS])

New Fields: - accessList: List of addresses and storage keys that will be accessed - Transaction type prefix: 0x01

Benefits: - Reduced gas costs for pre-declared storage access - Mitigates effects of EIP-2929 (cold/warm access costs)

Type 2: EIP-1559 Transactions

Status: ✅ Implemented (via ETC Olympia — ECIP-1111) EIP: EIP-1559

Structure: 

0x02 || rlp([chainId, nonce, maxPriorityFeePerGas, maxFeePerGas, gasLimit, to, value, data, accessList, signatureYParity, signatureR, signatureS])

New Fields: - maxPriorityFeePerGas: Maximum priority fee (tip) to miner - maxFeePerGas: Maximum total fee willing to pay - Replaces gasPrice with fee market mechanism

Gas Calculation: 

effectiveGasPrice = min(maxFeePerGas, baseFeePerGas + maxPriorityFeePerGas)
priorityFee = effectiveGasPrice - baseFeePerGas

Benefits: - Predictable base fees - Better UX (no more gas price guessing) - ETH burn mechanism (base fee is burned)

Type 3: Blob Transactions (EIP-4844)

Status: ❌ N/A (blob transactions not in ETC scope) EIP: EIP-4844

Structure: 

0x03 || rlp([chainId, nonce, maxPriorityFeePerGas, maxFeePerGas, gasLimit, to, value, data, accessList, maxFeePerBlobGas, blobVersionedHashes, signatureYParity, signatureR, signatureS])

New Fields: - maxFeePerBlobGas: Maximum fee per blob gas unit - blobVersionedHashes: Commitments to blob data (not included in block)

Blob Data: - Blobs are ~128KB each (4096 field elements × 32 bytes) - Not stored in execution layer state - Designed for rollup data availability - Separate gas market from regular transactions

Benefits: - Dramatically cheaper data availability for rollups - Separate blob gas pricing (independent of regular gas) - Temporary storage (blobs pruned after ~18 days)

Type 4: Account Abstraction Transactions (EIP-7702)

Status: ✅ Implemented (via ETC Olympia — ECIP-1121) EIP: EIP-7702

Structure: 

0x04 || rlp([chainId, nonce, maxPriorityFeePerGas, maxFeePerGas, gasLimit, to, value, data, accessList, authorizationList, signatureYParity, signatureR, signatureS])

New Field: - authorizationList: List of authorizations to temporarily set code for EOAs

Authorization Structure: 

case class Authorization(
  chainId: BigInt,
  address: Address,      // Contract address to delegate to
  nonce: BigInt,         // Account nonce for replay protection
  yParity: Byte,
  r: BigInt,
  s: BigInt
)

Mechanism: 1. EOA signs authorization to delegate to a contract 2. During transaction execution, EOA temporarily gets code from contract 3. Code is removed after transaction completes 4. Enables smart contract logic for EOAs

Benefits: - Account abstraction for EOAs without protocol changes - Batched transactions from EOAs - Gas sponsorship (someone else pays gas) - Custom signature schemes - Social recovery - Transaction batching

Security Considerations: - Authorization nonce prevents replay attacks - Chain ID prevents cross-chain replay - Temporary delegation limits attack surface - Must validate all authorizations before execution

Transaction Type Comparison

Feature Type 0 Type 1 Type 2 Type 3 Type 4
Gas Pricing Fixed Fixed Dynamic (EIP-1559) Dynamic + Blob Dynamic + Blob
Access Lists ❌ ✅ ✅ ✅ ✅
Base Fee ❌ ❌ ✅ ✅ ✅
Blob Data ❌ ❌ ❌ ✅ ❌
EOA Code Delegation ❌ ❌ ❌ ❌ ✅
Chain ID Optional ✅ ✅ ✅ ✅
Use Case Legacy Gas optimization Modern txs Rollup data Account abstraction

Implementation Status in Fukuii

Type Status Priority Notes
Type 0 ✅ Implemented N/A Fully supported
Type 1 ⚠️ Partial 🟠 High Access list parsing incomplete
Type 2 ❌ Missing 🔴 Critical Required for London compatibility
Type 3 ❌ Missing 🟡 Medium Required for Cancun compatibility
Type 4 ❌ Missing 🔴 Critical Required for Pectra compatibility

Consensus and Protocol Differences

Ethereum Classic vs Ethereum Mainnet

Feature Ethereum Classic Ethereum Mainnet
Consensus Proof of Work (Ethash) Proof of Stake
Block Time ~13 seconds 12 seconds (slots)
Block Reward 2.56 ETC (w/ reduction) N/A (tips only)
Difficulty Bomb Removed N/A (post-Merge)
DAO Fork Not applied Applied
EIP-1559 Not implemented Implemented
Beacon Chain Not applicable Required
Withdrawals Not applicable EIP-4895
Blob Transactions Not applicable EIP-4844

Key Protocol Differences

  1. Transaction Types:
  2. ETC: Type 0 (legacy) only

  3. ETH: Types 0, 1, 2, 3, 4 (legacy, access list, EIP-1559, blob, EIP-7702)

  4. Block Headers:

  5. ETC: Classic header structure with PoW fields

  6. ETH: Extended header with baseFeePerGas, withdrawalsRoot, blobGasUsed, excessBlobGas, parentBeaconBlockRoot

  7. Execution Payload (Post-Pectra):

  8. Additional field: requests (EIP-7685)

  9. Includes deposits, exits, and consolidation requests

  10. Chain ID:

  11. ETC: 61 (mainnet), 63 (Mordor)

  12. ETH: 1 (mainnet)

  13. Network Protocol:

  14. ETC: eth/63-68, snap/1

  15. ETH: eth/66-68, snap/1 (with extended message types)

  16. Validator Operations (Pectra):

  17. ETC: N/A (PoW)
  18. ETH: On-chain deposits (EIP-6110), execution-triggered exits (EIP-7002), validator consolidation (EIP-7251)

Testing and Validation

Ethereum Test Suite Compatibility

Fukuii includes the ethereum/tests submodule for compliance testing:

# Run EVM tests
sbt "testOnly *VMSpec"
sbt "Evm / test"

# Run blockchain tests
sbt "IntegrationTest / test"

Test Categories

Category Status Notes
General State Tests ✅ Passing Core EVM tests
Blockchain Tests ✅ Passing Pre-Merge blocks
VM Tests ✅ Passing Opcode tests
RLP Tests ✅ Passing Encoding tests
Transaction Tests ⚠️ Partial Type 0 only
Beacon Chain Tests ❌ Missing Post-Merge

  1. EVM Compliance: 

    # Run ethereum/tests GeneralStateTests
sbt "testOnly *GeneralStateTest*"

  2. Opcode Correctness: 

    # Run VM-specific tests
sbt "testOnly *OpCode*"

  3. Precompile Verification: 

    # Run precompiled contract tests
sbt "testOnly *PrecompiledContracts*"

  4. Fork Transition Testing: 

    # Test fork activation
sbt "testOnly *Fork*"

Implementation Roadmap

Phase 1: EIP-1559 Support (Estimated: 4-6 weeks)

  1. Week 1-2: Transaction type infrastructure
  2. Implement typed transaction envelope (EIP-2718)
  3. Add Type 1 (EIP-2930) access list transactions

  4. Add Type 2 (EIP-1559) transactions

  5. Week 3-4: Block header changes

  6. Add baseFeePerGas to block header
  7. Implement base fee calculation algorithm

  8. Update block validation

  9. Week 5-6: EVM changes

  10. Implement BASEFEE opcode (EIP-3198)
  11. Update gas price calculations
  12. Integration testing

Phase 2: Missing Cancun EIPs (Estimated: 3-4 weeks)

  1. Week 1: Transient storage (EIP-1153)
  2. Implement TLOAD/TSTORE opcodes

  3. Add transient storage tracking per transaction

  4. Week 2: MCOPY instruction (EIP-5656)

  5. Implement memory copy opcode

  6. Gas cost calculations

  7. Week 3: SELFDESTRUCT changes (EIP-6780)

  8. Modify SELFDESTRUCT behavior

  9. Track contract creation in same transaction

  10. Week 4: Testing and validation

Phase 3: Post-Merge Infrastructure (Estimated: 8-12 weeks)

  1. Weeks 1-4: Engine API
  2. Implement JSON-RPC Engine API
  3. Payload building and validation

  4. Fork choice rule updates

  5. Weeks 5-8: Beacon chain integration

  6. PREVRANDAO support (EIP-4399)
  7. Withdrawals processing (EIP-4895)

  8. Parent beacon block root (EIP-4788)

  9. Weeks 9-12: Testing and validation

  10. Hive test suite integration
  11. Devnet participation
  12. Full sync testing

Phase 4: Proto-Danksharding (Estimated: 6-8 weeks)

  1. Weeks 1-3: Blob transactions
  2. Type 3 transaction support
  3. KZG commitment handling

  4. Point evaluation precompile

  5. Weeks 4-6: Block changes

  6. Blob gas accounting
  7. Excess blob gas tracking

  8. BLOBBASEFEE opcode

  9. Weeks 7-8: Testing and validation

Phase 5: Pectra/Fusaka Support (Estimated: 10-14 weeks)

  1. Weeks 1-3: BLS12-381 Precompiles (EIP-2537)
  2. Implement 9 BLS12-381 precompiled contracts (0x0B - 0x13)
  3. G1/G2 point operations
  4. Pairing and mapping functions

  5. Extensive testing with official test vectors

  6. Weeks 4-5: Historical Block Hashes (EIP-2935)

  7. Implement system contract for block hash storage
  8. Update BLOCKHASH opcode logic

  9. Ring buffer implementation (8192 blocks)

  10. Weeks 6-8: Execution Layer Requests Framework (EIP-7685)

  11. Add requests field to execution payload
  12. Implement request encoding/decoding
  13. Update Engine API to v4

  14. Request validation and processing

  15. Weeks 9-10: On-chain Deposits (EIP-6110)

  16. Extract deposits from execution layer logs
  17. Add deposits field to payload
  18. Deposit validation (max 8192 per block)

  19. Integration with deposit contract

  20. Weeks 11-12: Execution-Triggered Exits (EIP-7002)

  21. Implement exit request system contract
  22. Add exits field to payload
  23. Exit request validation (max 16 per block)

  24. Public key and amount processing

  25. Weeks 13-14: EIP-7702 Transactions (Type 4)

  26. Authorization list parsing and validation
  27. Temporary code delegation mechanism
  28. Nonce verification for authorizations
  29. Gas accounting for delegated code
  30. Comprehensive security testing

Note on EIP-7251 and EIP-7549: These are primarily consensus layer changes with minimal execution layer impact beyond supporting consolidation requests in the general request framework.

Note on EIP-7594 (PeerDAS): This is a consensus layer networking change with no direct execution client implementation required.

Conclusion

With the Olympia hard fork (ECIP-1111/1112/1121), Fukuii achieves EVM compatibility well beyond the Berlin/Istanbul level. Olympia implements key EIPs from Ethereum's London, Cancun, and Pectra forks that are applicable to ETC's PoW chain:

Implemented via Olympia (ECIP-1111/1112/1121)

EIP From ETH Fork Description
EIP-1559 London Fee market with baseFee (treasury redirect on ETC)
EIP-3198 London BASEFEE opcode
EIP-1153 Cancun Transient storage (TLOAD/TSTORE)
EIP-5656 Cancun MCOPY opcode
EIP-6780 Cancun SELFDESTRUCT restriction
EIP-2935 Pectra Historical block hashes in state
EIP-2537 Pectra BLS12-381 precompiles (stubs)
EIP-7702 Pectra Set EOA Account Code (Type-4 tx)
EIP-7951 — P256VERIFY precompile
EIP-7623 — Floor data gas cost
EIP-7825 — Per-tx gas limit cap (30M)
EIP-7934 — Block RLP size cap (8 MiB)
EIP-7883 — ModExp gas repricing

Not Applicable to ETC (PoS/Beacon chain features)

The following Ethereum mainnet features are not applicable to ETC's Proof-of-Work consensus: - EIP-3675 (PoS transition), EIP-4399 (PREVRANDAO), EIP-4895 (withdrawals) - EIP-4844 (blob transactions), EIP-7516 (BLOBBASEFEE) - EIP-6110 (validator deposits), EIP-7002 (validator exits), EIP-7251 (MaxEB) - EIP-7685 (EL requests framework), EIP-7549 (committee index), EIP-7594 (PeerDAS)

Remaining Gaps

  1. BLS12-381 full crypto — stubs deployed, full implementation requires JVM BLS library
  2. EIP-2718 Type-1 access list transactions — parsed but not fully exercised in ETC
  3. DIFFICULTY vs PREVRANDAO — ETC uses DIFFICULTY (PoW), not PREVRANDAO

References

Official Ethereum Resources

Ethereum Classic Resources

Pectra/Fusaka Fork Resources

Engine API and Consensus

Testing and Validation

Document History

  • Initial Version: Pre-Pectra analysis (focusing on London through Cancun)
  • December 2025: Updated for Pectra/Fusaka fork activation
  • Current Version (March 2026): Updated for Olympia hard fork (ECIP-1111/1112/1121)
  • 14 EIPs moved from Missing/Partial to Implemented
  • Added BASEFEE, TLOAD, TSTORE, MCOPY opcodes as Implemented
  • Added P256VERIFY precompile (Implemented), BLS12-381 precompiles (Stubs)
  • Updated transaction type support: Types 2 and 4 now Implemented
  • Updated conclusion with Olympia implementation status summary
  • Pectra/Fusaka fork was activated on May 7, 2025
  • Added 9 new Pectra/Fusaka EIPs with detailed analysis
  • Added comprehensive transaction types section (Types 0-4)
  • Updated fork history timeline with Pectra activation
  • Revised priority classifications (EIP-2537 upgraded to High)
  • Added 10 new precompile addresses (1 from EIP-4844, 9 from EIP-2537)
  • Expanded implementation roadmap with Phase 5 (Pectra support)
  • Enhanced conclusion with Pectra-specific development impact analysis
  • Added comprehensive references for Pectra-related EIPs