# EPF Week 9–10 These two weeks focused on pushing forward both the FOCIL implementation and SSZ transaction work, with deeper testing and integration across Nimbus and EELS. Alongside this, I worked on debugging, aligning with spec discussions, and preparing next steps for broader interop testing. ## FOCIL Updates ### Development Progress - moving towrds actual testing - need to reconsile some changes - complete impl of the epoch based il storage on discussion witht he mentor from nimbus * Coordinate with ZKash on p2p side integration and fork-choice adjustments to ensure cross-module consistency. ## Pureth / SSZ Transactions (EIP-6404) ### Development Progress * Added SSZ transaction definitions to EELS, mirroring the current execution payload structure. * Began migrating RLP tests into SSZ equivalents to ensure feature parity. * Integrated `remerkleable` for tree diffing and SSZ serialization in tests, with temporary workarounds where library support is incomplete. * Initial implementation in Nimbus-EL to parse, validate, and serialize SSZ transactions. * work on going to start producing the inital ssz blocks and to validate them(in progress) * had problems in the decoding for the ssz in nim and also the merklelization which was solved partly(blocker as of now) ### Testing * Set up EELS tests for legacy, dynamic fee, blob, and 7702 transaction types under SSZ encoding. * Have a hive instace with my version of the tests running * co-ordinate with the others to have a testnet ready withing the first half of the next month * Began constructing receipt tests for SSZ transaction roots and log handling. * Implemnted some local patchs in the eels to have stuff up and ready ### Next Steps * Expand tests for mixed transaction lists and round-trip validation across Nimbus/EELS. * Begin looking into migration paths from RLP → SSZ in execution payloads. * Planned scope for next iteration: merging FOCIL fork-choice into Nimbus-CL and stabilizing SSZ tx testing across clients in pureth.