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 { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";
const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });
// Build set_code_without_checks call
const code = 0;
const call = api.tx[stringCamelCase("System")][stringCamelCase("set_code_without_checks")](
code
);Runtime Info
- Pallet Index
- 0
- Call Index
- 3
- First Version
- v101
- Current Version
- v393