Merge pull request #654 from OffchainLabs/Add-comments-to-precompile-…

…howto

Add comments to precompile howto

arbitrum-docs/launch-orbit-chain/how-tos/customize-precompile.mdx

@@ -10,6 +10,16 @@ import PublicPreviewBannerPartial from '../partials/_orbit-public-preview-banner
 
 <PublicPreviewBannerPartial />
 
+:::caution
+
+The guidance in this document will work only if you use `eth_call` to call the new precompiles. If you're calling from other contracts or adding non-view/pure methods, this approach will break block validation.
+
+To support these additional use-cases, stay tuned for instructions that walk you through the process of updating the Wasm module root.
+
+If you want to test modifying the State Transition System (STS) before this guidance is available, use the `--node.staker.dangerous.without-block-validator` config flag when you start your node.
+
+:::
+
 There are two ways to customize your chain's precompiles:
 
 1. Add new methods to an existing [precompile][precompile_impl_dir_link].