> For the complete documentation index, see [llms.txt](https://docs.lumia.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lumia.org/build/faqs.md).

# FAQs

Below you will find some common questions and answers around Lumia zkEVM.

<details>

<summary>Which EVM op_codes are different on Lumia zkEVM?</summary>

* SELFDESTRUCT: removed by SENDALL&#x20;
* EXTCODEHASH: returns hash contract bytecode from zkEVM state tree (do not check if the account is empty)
* DIFFICULTY: returns 0
* BLOCKCHASH: returns all previous block hashes (not just the last 256 blocks)&#x20;
* BLOCKCHASH is the state root at the end of a processable transaction and it is stored on the system smart contract
* NUMBER: number of processable transactions

</details>

<details>

<summary>Which op_codes are missing from Lumia zkEVM?</summary>

Lumia zkEVM supports all opcodes but SHA256, BLAKE and PAIRINGS.

</details>

<details>

<summary>Which precompiled SmartContract functions does Lumia zkEVM support?</summary>

ecRecover and identity are presently supported. Others return a revert.

</details>