Ethereum delays Glamsterdam on Hoodi, withdraws gas limit increase to 200 million units
Key Facts
The Ethereum Foundation announced a delay to the activation of the Glamsterdam upgrade on the Hoodi testnet, scheduled for 26 October, to allow further investigation into how Ethereum Improvement Proposal 8037 interacts with existing smart contracts on the mainnet. The decision includes withdrawing the scheduled increase in Hoodi's gas limit to 200 million units, which was tied to the upgrade's activation. The foundation said the investigation focuses on how the proposed changes interact with contracts already in place, prompting it to postpone the testnet activation. It said withdrawing future upgrade configurations does not roll back the Hoodi blockchain or rewrite its history. Mainnet users and ETH holders need take no action in response to the delay announcement, according to the foundation.
The risks outlined by ChainSecurity concern how contracts behave when a call fails and how a change in gas accounting could affect the handling of that failure. The company said an attacker could deliberately supply a call with insufficient gas while leaving enough to record the failure permanently or remove the ability to retry. It added that reversing state creation during a transaction could immediately return state gas. That return could allow a failure-handling path to complete that would previously have reverted, even with the contract's code unchanged. The company recommended that a failed call trigger a revert of the entire operation wherever possible. Where failure handling is necessary, it urged developers to "preserve a path to recover the operation" rather than eliminate the possibility of completing it later.
The impact of the gas accounting adjustment extends to how some contracts and tools measure work performed, according to the text of Ethereum Improvement Proposal 8037. Subtracting two readings of remaining gas could produce a negative value under the proposed change. The proposal states that deployed contracts using this measurement cannot be fixed, making the measurement method itself part of the change's impact on existing applications. In another cost adjustment, the network state access proposal raises the cost of cold account access from 2,600 to 3,000 gas units. The proposal keeps the cost of cold storage access at 2,100 units, treating account access differently from storage access.
An earlier Ethereum Foundation guide on repricing addressed problems that emerged when replaying historical transactions to test the changes. The guide said "most observed issues are resolved by increasing the gas limit," an assessment tied to those test results. It also directed wallet developers to update gas estimation mechanisms to reflect the revised costs. The call included infrastructure developers whose tools rely on estimates of the gas needed to execute transactions. The foundation warned that relying on previously stored gas constants would result in underestimates and, consequently, failed transactions.
The Hoodi delay follows Glamsterdam's activation on the Sepolia testnet on 6 October, according to the foundation's earlier announcement of the testing schedule. The proposed changes include separating execution validation from consensus validation, according to the relevant proposal document. The separation aims to give validators more time to process execution, rather than combining both tasks in the critical period before voting. In an earlier capacity increase, the foundation said the community had raised the mainnet gas limit from 30 million to 60 million units at the time of the protocol priorities update. That increase concerns the mainnet, while the scheduled increase to 200 million units withdrawn with the delay concerns the Hoodi testnet.
For Hoodi operators, the delay announcement lists Lodestar version 1.50.1 and Besu version 26.10.1 among the client releases that incorporate the activation delay. The foundation asks operators to update software that still schedules Glamsterdam for the old date. The request also applies to custom network configurations, which must be adjusted to match Hoodi's revised settings. The foundation did not set a replacement activation date for the upgrade on Hoodi, saying "a new activation date has not been determined." Glamsterdam's mainnet activation date was already undecided in the earlier Hoodi announcement. The earlier protocol priorities document used December 2026 as an assumption for Glamsterdam's delivery when calculating the pace of upgrades, without adopting it as a specific activation date.