What you need to know before deploying

  1. Have metamask account on the target chain with a sufficient number of native tokens for deployment
  2. Read how to deploy contracts via Remix here https://docs.linea.build/build-on-linea/quickstart/deploy-smart-contract/remix
  3. Read how to verify contracts in explorer
  4. Add target chain configs to backend and frontend Add Bridge support for new chain
  5. Prepare target chain and token links:
    1. Target chain explorer: for example linea https://lineascan.build/
    2. Target Original ERC20 token address: for example (USDC): https://lineascan.build/token/0x176211869ca2b568f2a7d4ee941e073a821ee1ff

Deploy Steps:

  1. Deploy HRC20 token wrapper to Harmony

    1. Generate sources here https://wizard.openzeppelin.com/ (Mint, Burn, Pause, Roles) (name: chain prefix + Original name)
    2. Go to https://remix.ethereum.org, create new file and paste sources
    3. Add custom decimals if needed
    function decimals() public pure override returns (uint8) {
		return 6;
}
    1. Build without optimisation with latest solidity version
    2. Deploy to Harmony

  2. Deploy HRC20Proxy contract

    1. Get ERC20Proxy flattened sources from here https://github.com/harmony-one/solidity-examples/blob/78c650cfb83325dc1681de145c203a47b848428c/flattened-contracts/proxyERC20WithMint.sol
    2. Go to https://remix.ethereum.org, create new file and paste sources
    3. Build without optimisation with latest solidity version (also check evm version for target chain)
    4. Deploy to Harmony Network
      1. ProxyToken address: token address from 1 step
      2. lzEndpoint: address from here https://layerzero.gitbook.io/docs/technical-reference/mainnet/supported-chain-ids

  3. Deploy ERC20Proxy contract

    1. Get ERC20Proxy flattened sources from here https://github.com/harmony-one/solidity-examples/blob/78c650cfb83325dc1681de145c203a47b848428c/flattened-contracts/proxyERC20.sol
    2. Go to https://remix.ethereum.org, create new file and paste sources
    3. Build without optimisation with latest solidity version (also check evm version for target chain)
    4. Deploy to External Network (Linea)
      1. ProxyToken address: original token address
      2. lzEndpoint: address from here https://layerzero.gitbook.io/docs/technical-reference/mainnet/supported-chain-ids

Contracts configuring:

You can read more about Proxy configuring here:

  1. Set Mint Role for HRC20 token
  2. Set Trusted remote (setTrustedRemoteAddress) for Harmony ProxyHRC20
  3. Set Trusted remote (setTrustedRemoteAddress) for External ProxyERC20

Update backend & frontend configurations:

  1. Create Token Configuration

    {
    hrc20Address: '0x9c5C877DB2A5a37733Fe1a0bdcae8411Cdc8c5B3',
    erc20Address: '0x176211869ca2b568f2a7d4ee941e073a821ee1ff',
    proxyERC20: '0x8a0167fC1Ef2E9492a1Eb978A9dA9137Ba25BB1B',
    proxyHRC20: '0xbA21f99d1067B8aE09f4f162e0528cB3FDb4FeD2',
    name: 'USD Coin (Linea)',
    symbol: 'USDC',
    decimals: '6',
    totalLocked: '0',
    totalSupply: '0',
    totalLockedNormal: '0',
    totalLockedUSD: '0',
    token: TOKEN.ERC20,
    type: TOKEN.ERC20,
    network: NETWORK_TYPE.LINEA,
    image: '/usdc.svg',
    adapterParams: '0x',
  },

  2. Add config to Frontend

https://github.com/harmony-one/layerzero-bridge.frontend/commit/abedb14b9e73ae9d124ca04e66eda06b8fa4cdb3