set_code_without_checks
Call v101 → current #3Set runtime code without validation (root only, dangerous).
View calls on chainCall Workflow
This diagram shows the call execution flow: starting with set_code_without_checks, passing through validation
(signature, nonce, mortality, fee payment), then pre-dispatch checks, followed by dispatch which emits events: CodeUpdated and modifies storage: LastRuntimeUpgrade, and finally post-dispatch where ExtrinsicSuccess is emitted and fees are settled.
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Used by: validatorsdevelopers
The Big Picture
Dangerous escape hatch that bypasses version checks. Only use when normal path fails.
Use Cases
- Emergency fixes
- Development testing
- Recovery from broken upgrades
From Chain Metadata
Set the new runtime code without doing any checks of the given `code`. ## Complexity `O(C)` where `C` length of `code`
Input Parameters
| # | Name | Type | Description |
|---|---|---|---|
| 0 | code | Vec<u8> Vec | code (Vec<u8>) |
Permissions
Origin
Unknown
Required Role
Permission data inferred from metadata. May be incomplete.
Requirements
- Caller is root/sudo
- Valid WASM code
Effects
Events Emitted
Storage Modified
Postconditions
- Runtime code deployed regardless of version
Side Effects
- Bypasses all safety checks
- Could brick the chain
Code Examples
import { createClient, Binary } from "polkadot-api";
import { getWsProvider } from "polkadot-api/ws";
import { sub } from "@polkadot-api/descriptors"; // generated by: npx papi add sub -w wss://entrypoint-finney.opentensor.ai:443
const client = createClient(getWsProvider("wss://entrypoint-finney.opentensor.ai:443"));
const api = client.getTypedApi(sub);
// Build set_code_without_checks call (typed, named args)
const code = Binary.fromOpaque(new Uint8Array(0));
const tx = api.tx.System.set_code_without_checks({
code,
});Runtime Info
- Pallet Index
- 0
- Call Index
- 3
- First Version
- v101
- Current Version
- v411