# Fusaka (EIP-7607) Retrospective - All Clients **Analysis Period:** Sep 22, 2024 - Dec 22, 2025 **Mainnet Activation:** December 3, 2025 ### Prysm - Mainnet Fork Bug Post-mortems available: - [potuz's analysis](https://www.potuz.net/posts/fulu-bug/) - [Prysm team post-mortem](https://prysm.offchainlabs.com/docs/misc/mainnet-postmortems/) --- ## Consensus Layer Clients ### Prysm **Repository:** https://github.com/OffchainLabs/prysm #### Important | Issue | Description | |-------|-------------| | [#15973](https://github.com/OffchainLabs/prysm/issues/15973) | Prysm forks when missing slots | | [#15951](https://github.com/OffchainLabs/prysm/issues/15951) | Data column sidecar proposer index caching | | [#15956](https://github.com/OffchainLabs/prysm/issues/15956) | KZG verification disagrees with others | | [#16125](https://github.com/OffchainLabs/prysm/issues/16125) | SIGSEGV in init sync | #### Other | Issue | Description | |-------|-------------| | [#16096](https://github.com/OffchainLabs/prysm/issues/16096) | Periodic sync loss (slot%2048==96) | --- ### Lighthouse **Repository:** https://github.com/sigp/lighthouse #### Important | Issue | Description | |-------|-------------| | [#8101](https://github.com/sigp/lighthouse/pull/8101) | Proposer calculation bugs post-Fulu | | [#8528](https://github.com/sigp/lighthouse/pull/8528) | Wrong Fork in verify_header_signature | | [#7961](https://github.com/sigp/lighthouse/pull/7961) | DA checker race condition | | [#8121](https://github.com/sigp/lighthouse/pull/8121) | Fork calculation at boundaries | #### Other | Issue | Description | |-------|-------------| | [#7305](https://github.com/sigp/lighthouse/issues/7305) | Verify signatures during backfill | --- ### Teku **Repository:** https://github.com/Consensys/teku #### Important | Issue | Description | |-------|-------------| | [#10232](https://github.com/Consensys/teku/issues/10232) | flag does not trigger backfill | | [#9824](https://github.com/Consensys/teku/issues/9824) |OOM due to "Failed to remove operations from pools for now canonical block" | | [#10110](https://github.com/Consensys/teku/issues/10110) | Syncing stalls after NullPointerException | | [#10223](https://github.com/Consensys/teku/issues/10223) | concurrentModificationException in batch sync | | [#10221](https://github.com/Consensys/teku/issues/10221)| exception in DasPreSampler | | [#10185](https://github.com/Consensys/teku/issues/10185) | Sync may stall if SimpleSidecarRetriever's RPC calls fail | --- ### Nimbus **Repository:** https://github.com/status-im/nimbus-eth2 #### Important | Issue | Description | |-------|-------------| | [#7778](https://github.com/status-im/nimbus-eth2/issues/7778) | [BPO at genesis broken config]( https://github.com/status-im/nimbus-eth2/pull/7788) | | [#7794](https://github.com/status-im/nimbus-eth2/pull/7794) | SSZ DataColumnSidecar invalid offset | | [#7763](https://github.com/status-im/nimbus-eth2/pull/7763) | fix supernode logic | | [#7528](https://github.com/status-im/nimbus-eth2/pull/7528)| column serving issue and other fixes | --- ### Grandine **Repository:** https://github.com/grandinetech/grandine #### Important | Issue | Description | |-------|-------------| | [#516](https://github.com/grandinetech/grandine/issues/516) | Panic on invalid data columns | --- ### Lodestar **Repository:** https://github.com/ChainSafe/lodestar #### Important | Issue | Description | |-------|-------------| | [#8629](https://github.com/ChainSafe/lodestar/issues/8629) | Network thread bottleneck | | [#8624](https://github.com/ChainSafe/lodestar/issues/8624) | writeBlockInputToDb blocks 750ms | | [#8623](https://github.com/ChainSafe/lodestar/issues/8623) | DataColumnSidecar deserialization 100-700ms | | [#8411](https://github.com/ChainSafe/lodestar/issues/8411) | Peer downscoring disabled | | [#8488](https://github.com/ChainSafe/lodestar/issues/8488) | Proposer lookahead 300-350ms on epoch | --- ## Execution Layer Clients ### Geth **Repository:** https://github.com/ethereum/go-ethereum #### Important | Issue | Description | |-------|-------------| | [#32577](https://github.com/ethereum/go-ethereum/pull/32577) | core/txpool/blobpool: Do not use blobs with wrong sidecar version while building block after Osaka | | [#32568](https://github.com/ethereum/go-ethereum/pull/32568) | Fix modexp calculation bug | | [#32714](https://github.com/ethereum/go-ethereum/pull/32714) | fix nil pointer dereference in Osaka | | --- ### Nethermind **Repository:** https://github.com/NethermindEth/nethermind #### Important | Issue | Description | |-------|-------------| | [#9999](https://github.com/NethermindEth/nethermind/pull/9999) | Fix blob length | | [#9894](https://github.com/NethermindEth/nethermind/issues/9894) | Blob transaction proof version | --- ### Besu **Repository:** https://github.com/hyperledger/besu #### Important | Issue | Description | |-------|-------------| | [#9187](https://github.com/hyperledger/besu/issues/9187) | ArrayIndexOutOfBounds in block selection | | [#9186](https://github.com/hyperledger/besu/issues/9186) | ConcurrentModificationException | | [#9548](https://github.com/hyperledger/besu/pull/9548) | Check static gas cost before accessing beneficiary in SELFDESTRUCT | | [#9146](https://github.com/hyperledger/besu/pull/9146) | Add explict check for points-on-curve in p256_verify| --- ### Erigon **Repository:** https://github.com/erigontech/erigon #### Important | Issue | Description | |-------|-------------| | [#17025](https://github.com/erigontech/erigon/issues/17025) | Wrong trie root on valid block | | [#18213](https://github.com/erigontech/erigon/issues/18213) | Stuck at Fulu fork boundary | | [#17123](https://github.com/erigontech/erigon/issues/17123) | Block production stops after 65 blocks | | [#18470](https://github.com/erigontech/erigon/pull/18470) | fix: prevent Exp() from mutating input base parameter | | [#18309](https://github.com/ledgerwatch/erigon/pull/18309) |RLPTooLong | --- ### Reth **Repository:** https://github.com/paradigmxyz/reth #### Important | Issue | Description | |-------|-------------| | [#20596](https://github.com/paradigmxyz/reth/pull/20596) | fix(storage): rocksdb consistency check on startup |
Last changed by  
 
parithosh.jayanthi@ethereum.org
35

Read more

Gas repricing workflow

flowchart TD Nums[Gas repricing in a doc] File[Script or Makefile] STEELRepo[STEEL<br/>repo<br/>PR with the title repricing] PitstopGeth[CI trigger on PR for pitstop geth<br/> branch called repricing/geth-repricing] STEELFill[STEEL<br/>fill using above branch <br/>repricing.tar.gz] PitstopAll[pitstop all<br/>client images] GABench[Gas<br/>benchmarker] Nums --> File

11/26/2025
Mekong deprecation Announcement

The Mekong devnet was meant to be a playground for wallet developers to experiment with UX changes and for stakers to gain confidence in the upcoming Pectra changes. The Pectra network upgrade has been activated on the Ethereum Sepolia and Holesky testnets. These networks can now be used to test the Pectra upgrade features. In light of this, we'd like to announce the deprecation of the Mekong testnet on 7th March, 2025. Application and tooling developers are encouraged to use Sepolia to test applications, smart contracts, and other EVM functionality. Its permissioned validator set provides a stable test environment. Alternatively, many local development environments allow for testing against copies of the Ethereum mainnet state. Stakers and infrastructure providers concerned with protocol-level testing are encouraged to wait for the Holesky testnet to finalize, or to await an announcement on the Ethereum R&D discord for an alternate testing location. For validator setup testing, stakers should also consider the Ephemery testnet. This network resets weekly and enables lightweight end-to-end testing of the validator lifecycle.

3/6/2025
How to create a shadowfork

Introduction: shadowfork Theory: General info: A chain consists of an Execution layer(EL) and a Consensus layer(CL) The EL is responsible for state (transactions, history, etc) and the CL is responsible for consensus (agreement on chain head) at a high level The EL is driven by the CL. i.e, The CL decides what the head of the chain is and the EL must accept that decision (mostly) The CL asks the EL to produce blocks, these blocks are placed in the EL chain as well as execution_payloads in the CL slot. This links the CL slot to the EL chain (leaving out caveats here) When the CL sends the request to produce a block, it also sends information about the block to build on top of

3/5/2025
Verkle transition

Considerations Resource use: CPU, Disk, Cost, I/O Syncing and Sync complexity increase Complexity of Implimentation and Testing Time for conversion to take place Ideological Methods Overview

1/18/2024
Read more from parithosh.jayanthi@ethereum.org
Published on HackMD