Fusaka Upgrade: CFI EIPs overview

Ethereum never stands still.

While the Pectra upgrade is approaching, devs are already looking ahead, and Fusaka is next.

Recently several new EIPs have just reached CFI status. Before diving into the each EIP, a short reminder how the process works.

So, when a new hard fork is in the works, EIPs go through several stages:

• PFI (Proposed for Inclusion)This means a developer or client team is suggesting the EIP for the next upgrade. It’s up for discussion, but no consensus yet.
• CFI (Considered for Inclusion)There’s general agreement among client teams that the EIP is worth including, but it’s not finalized yet.
• SFI (Scheduled for Inclusion)It is final stage. The EIP is agreed on by all teams and will be included in the next upgrade.

Fusaka EIPs that reached CFI status:

EIP-7823: Set upper bounds for MODEXP

This proposal sets a maximum size for inputs to the MODEXP precompile. Currently, very large inputs make testing harder and increase the risk of bugs. Limiting input size reduces that risk and improves predictability.

MODEXP has caused several bugs, often from unusually large inputs. Its pricing is complex due to the lack of limits. While pricing won’t change yet, setting limits could simplify it later.

These limits also help pave the way for eventually replacing MODEXP with EVM code using tools like EVMMAX.

EIP-7825: Transaction Gas Limit Cap

A cap of 30 million gas per transaction is being introduced to improve network stability, reduce exposure to certain denial-of-service (DoS) attacks, and make transaction costs more predictable.

This change becomes especially important as Ethereum explores increasing the overall block gas limit, ensuring that no single transaction can disproportionately affect the network.

EIP-7907: Meter Contract Code Size and Increase Limit

This EIP increases the contract code size limit from 24KB to 256KB and introduces a gas fee of 2 gas per 32-byte word for contracts over 24KB. It also raises the initcode size limit from 48KB to 512KB.

While the original 24KB limit aimed to prevent DoS attacks, it restricted legitimate use cases. This EIP ensures larger contracts are possible, with users paying for the additional resources consumed, in line with Ethereum's gas model.

EIP-7762: Increase MIN_BASE_FEE_PER_BLOB_GAS

This proposal suggests raising the minimum base fee per blob gas to speed up the price discovery process for blob space. Additionally, it resets the excess blob gas to zero to prevent abrupt spikes in the blob base fee. This adjustment aims to improve price stability as blob usage increases and to prepare for future adjustments in blob capacity.

EIP-7918: Blob base fee bounded by execution cost

To improve fee stability, this EIP ensures that blob fees don’t fall below the cost of executing the transaction that carries them. When execution gas dominates, the blob fee signal can break, leading to sharp drops, unstable pricing and poor user experience.

By enforcing fee parity between blobs and execution, the proposal keeps pricing predictable and aligned with real network costs while avoiding unnecessary fee spikes during demand shifts.

Note: Only one of the last two EIPs (7762 or 7918) will be included in the Fusaka upgrade. The final choice is still under discussion and may involve further evaluation and potential modifications before implementation.

https://preview.redd.it/ew4azb0exmve1.png?width=3200&format=png&auto=webp&s=2891887b7e0398a67b4e9bd7bd4b03a9f946def4