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# System prepended metadata

title: 'Dev Update Week 12: Implementation of the Hybrid Ethereum VM 1'

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# Dev Update Week 12: Implementation of the Hybrid Ethereum VM 1

**Developer:** Developeruche
**Week Ending:** September 7, 2025

### Summary

Building on the architectural research from Week 11, this week marked the beginning of hands-on implementation. The focus was on translating the high-level design of a hybrid Ethereum execution engine into a working prototype. Progress is currently at **\~50% completion**, with core components of the RISC-V execution sandbox and bytecode differentiation already underway.

### Accomplishments This Week

* **RISC-V Sandbox Setup:** Established the basic RISC-V VM environment that will act as the execution engine for smart contracts.
* **Bytecode Identification Logic:** Implemented preliminary logic to detect whether a contract is **legacy EVM**, **EOF-EVM**, or **RISC-V**, based on magic number prefixes.
* **`mini-evm` Emulator Foundations:** Began building the `mini-evm` system contract, with early opcode handling mapped into RISC-V syscalls.
* **Integration Progress:** Designed the interface for connecting blockchain state operations (`SSTORE`, `SLOAD`, `CALL`) to RISC-V syscalls.

[code](https://github.com/developeruche/hybrid)
[mini evm code](https://github.com/developeruche/hybrid/tree/main/bins/mini-evm-interpreter)

### Next Steps & Goals for Next Week

1. **Finish `mini-evm` Opcode Handling:** Expand support for a wider set of EVM instructions to improve coverage.
2. **Gas Metering Model Exploration:** Begin drafting a gas metering strategy that balances fairness across both RISC-V and EVM execution paths.
3. **Testing and Validation:** Run basic test cases of EVM contracts executed via the `mini-evm` inside the RISC-V sandbox.
4. **Documentation:** Start drafting internal documentation to capture design decisions and implementation progress.

### Challenges & Learnings

* **Challenge: Bridging State Access:** Designing `syscalls` that safely and efficiently expose blockchain state to the RISC-V environment has proven complex.
* **Learning: Incremental Development Works Best:** Tackling the hybrid design step-by-step (sandbox → bytecode detection → emulator) allows for better validation and avoids overwhelming complexity.
* **Learning: Backward Compatibility Is Achievable:** Early prototypes suggest that maintaining seamless support for legacy EVM contracts is feasible, strengthening confidence in the hybrid model.