# Ethereum Protocol Fellowship - The Third Cohort (Update 5)

This is the fifth update for Ethereum Protocol Fellowship - The Third Cohort.

In the past two weeks, I continued with the development of the user operation pool of the EIP-4337 (AA) Bundler.

- Description: https://github.com/eth-protocol-fellows/cohort-three/blob/master/projects/4337-bundler-rust.md
- Architecture and specification: https://hackmd.io/@Vid201/aa-bundler-rust
- GitHub repository: https://github.com/Vid201/aa-bundler/

## Updates

List of updates:
1. Presented project during office hours.
2. Found a bug in the eth-infinitism's library @account-abstraction/sdk and reported it to the team, which already fixed it: https://github.com/eth-infinitism/bundler/commit/286eddb84192373531da6630f91f1ddada5e83de
3. Implemented packing of user operation and computing hash over it: https://github.com/Vid201/aa-bundler/commit/cf95912b5243e366fba69c270713f1ce2fd4d2a5
4. Wrote a bunch of tests for user operations.
5. More or less completed sanity checks on received user operations: https://github.com/Vid201/aa-bundler/pull/24

## Next steps

I am continuing with the simulation of user operations and additional checks that comes alongside, such as which opcodes are allowed and which are not. After finishing with the private user operation pool, I will continue implementing JSON RPC calls and the bundling itself.