Update Gas Price on EVM Rollup

Overview

You may want to use an ERC-20 token as the fee token instead of the tokens issued by the Cosmos Bank module. To do this, you need to update the chain parameters of the EVM module and set the fee token to the desired ERC-20 token. This change must be made using a admin account with the authority to modify chain parameters.

The deployed ERC20 token must inherit the InitiaERC20 contract.

Prerequisites

• NodeJS
• Install minitiad

Update Chain Parameters

1. Set Up Operator Key

Add your operator key to the local keyring. This key will be used to sign transactions.

minitiad keys add operator --recover --key-type secp256k1 --coin-type 118

• --recover: Recovers a key from a mnemonic phrase.
• --key-type secp256k1: Common key type used in Cosmos SDK-based chains.
• --coin-type 118: Standard coin type for Cosmos-based chains.

2. Create Update Messages

You need to create messages for both:

• opchild.v1.MsgUpdateParams
• evm.v1.MsgUpdateParams

You can get the current opchild and evm parameters by querying:

curl ${REST_ENDPOINT}/opinit/opchild/v1/params

# 📌 Example: https://rest-yominet-1.anvil.asia-southeast.initia.xyz/opinit/opchild/v1/params
# {
#   "params": {
#     "max_validators": 100,
#     "historical_entries": 10000,
#     "min_gas_prices": [
#       {
#         "denom": "GAS",
#         "amount": "30000000.000000000000000000"
#       }
#     ],
#     "bridge_executors": [
#       "init1jaz6hxkn8cx9dxjwrjwy4v2qs2u09pf25ztcam"
#     ],
#     "admin": "init1ppzptg22xx259zzpgpejphzcvjmc7r2ff984c3",
#     "fee_whitelist": [
#       "init1ppzptg22xx259zzpgpejphzcvjmc7r2ff984c3",
#       "init1ppzptg22xx259zzpgpejphzcvjmc7r2ff984c3",
#       "init1jaz6hxkn8cx9dxjwrjwy4v2qs2u09pf25ztcam",
#       "init1fvhhqk3tvv08vd5gmsp45x8tkzhcwv3ly8kn78"
#     ],
#     "hook_max_gas": "3000000"
#   }
# }

curl ${REST_ENDPOINT}/minievm/evm/v1/params

# 📌 Example: https://rest-yominet-1.anvil.asia-southeast.initia.xyz/minievm/evm/v1/params
# {
#   "params": {
#     "extra_eips": [],
#     "allowed_publishers": [],
#     "allow_custom_erc20": true,
#     "allowed_custom_erc20s": [],
#     "fee_denom": "GAS",
#     "gas_refund_ratio": "0.500000000000000000",
#     "num_retain_block_hashes": "0"
#   }
# }

Create a JSON file named messages.json with the following content:

// messages.json
{
  "messages": [
    {
      "@type": "/opinit.opchild.v1.MsgUpdateParams",
      "authority": "init1gz9n8jnu9fgqw7vem9ud67gqjk5q4m2w0aejne",
      "params": {
        "max_validators": 100,
        "historical_entries": 10000,
        "min_gas_prices": [
          {
            "denom": "umin",
            "amount": "1000000000" 
          }
        ],
        "bridge_executors": [
          "init1jaz6hxkn8cx9dxjwrjwy4v2qs2u09pf25ztcam"
        ],
        "admin": "init10g75rf30pwpkgu68yr8uh4gm824xajg09233xr",
        "fee_whitelist": [
          "init1ppzptg22xx259zzpgpejphzcvjmc7r2ff984c3",
          "init1jaz6hxkn8cx9dxjwrjwy4v2qs2u09pf25ztcam",
          "init1fvhhqk3tvv08vd5gmsp45x8tkzhcwv3ly8kn78"
        ],
        "hook_max_gas": "3000000"
      }
    },
    {
      "@type": "/minievm.evm.v1.MsgUpdateParams",
      "authority": "init1gz9n8jnu9fgqw7vem9ud67gqjk5q4m2w0aejne",
      "params": {
        "extra_eips": [],
        "allowed_publishers": [],
        "allow_custom_erc20": true,
        "allowed_custom_erc20s": [],
        "fee_denom": "umin",
        "gas_refund_ratio": "0.500000000000000000",
        "num_retain_block_hashes": "256"
      }
    }
  ]
}

• Message 1: /opchild.v1.MsgUpdateParams

Field	Explanation
max_validators	Max number of active validators
historical_entries	Number of historical blocks to retain
min_gas_prices.denom	Native token denomination
min_gas_prices.amount	Minimum gas price in smallest unit
bridge_executors	Allowed bridge executor address
admin	Admin address with authority to update params
fee_whitelist	Addresses exempted from fees
hook_max_gas	Maximum gas for execution hooks

• Message 2: /evm.v1.MsgUpdateParams

Field	Explanation
extra_eips	Additional Ethereum Improvement Proposals to enable
allowed_publishers	List of allowed smart contract publishers
allow_custom_erc20	Whether to allow custom ERC-20 tokens
allowed_custom_erc20s	Whitelisted custom ERC-20 contracts
fee_denom	Fee denomination used by EVM
gas_refund_ratio	Refund ratio on unused gas
num_retain_block_hashes	Number of recent block hashes to retain

authority address will be a opchild module account regardless of the field you want to update. To get the authority address, you can use the following command:

curl ${REST_ENDPOINT}/cosmos/auth/v1beta1/module_accounts/opchild

# 📌 Example: https://rest-yominet-1.anvil.asia-southeast.initia.xyz/cosmos/auth/v1beta1/module_accounts/opchild
# {
#   "account": {
#     "@type": "/cosmos.auth.v1beta1.ModuleAccount",
#     "base_account": {
#       "address": "init1gz9n8jnu9fgqw7vem9ud67gqjk5q4m2w0aejne",
#       "pub_key": null,
#       "account_number": "2771",
#       "sequence": "0"
#     },
#     "name": "opchild",
#     "permissions": [
#       "minter",
#       "burner"
#     ]
#   }
# }

If you set empty values on the field, it will be set to the empty value, which may cause issues. Be careful to set any fields you do not wish to change with their existing values. Update your values carefully — especially the admin address.

Save the content above as messages.json.

3. Execute the Update Transaction

Submit the parameter update messages using the CLI:

minitiad tx opchild execute-messages ./messages.json \
  --from operator --chain-id yominet-1 \
  --node https://rpc-yominet-1.anvil.asia-southeast.initia.xyz

4. Verify the Updated Parameters

Once the transaction is successful, verify the updated parameters:

minitiad q opchild params \
  --node https://rpc-yominet-1.anvil.asia-southeast.initia.xyz

minitiad q evm params \
  --node https://rpc-yominet-1.anvil.asia-southeast.initia.xyz

These queries will return the live parameter state for both modules.