# Submitting Transactions from L1 (/docs/unichain/technical-information/submitting-transactions-from-l1)

Submit transactions from Ethereum L1 to Unichain using the Optimism Portal contract.

## Withdraw ETH via an L1 Transaction
Initiating an L2 withdrawal from L1 on the OP Stack is a three-step process:

1. Initiate the withdrawal on L2 (either via an L1 deposit transaction or directly on L2).
2. Relay the withdrawal to L1.
   * You can do this after the withdrawal occurs on L2 and an output is proposed on L1.
   * This step can take place up to about 1 hour after the withdrawal is initiated on L2.
3. Finalize the withdrawal on L1.
   * This step is available no sooner than 7 days after relay because of the OP Stack fault challenge period.

## Unichain Contract Addresses
```bash
PORTAL_ADDR=0x0bd48f6B86a26D3a217d0Fa6FfE2B491B956A7a2
DGF_ADDRESS=0x2F12d621a16e2d3285929C9996f478508951dFe4
```

## Initiate a Withdrawal from L1
Via the command line, call the Optimism Portal Proxy on L1 to create an L2 deposit transaction. The L2 transaction will send the ETH to the `L2ToL1Messenger` contract to initiate a withdrawal. You can withdraw up to your total balance on L2 (use `cast balance $ADDR -r $L2_RPC_URL` to get your ETH balance on L2).

```bash
cast send $PORTAL_ADDR \
    "depositTransaction(address _to, uint256 _value, uint64 _gasLimit,bool _isCreation,bytes memory _data)" \
    0x4200000000000000000000000000000000000016 \
    $AMOUNT_IN_WEI_TO_WITHDRAW \
    300000 \
    false \
    0x --private-key=$PK
```

After your deposit has landed on L1, determine your L2 transaction hash:

```bash
git clone https://github.com/ethereum-optimism/optimism
cd optimism/op-chain-ops/cmd

# Run the following command to get your L2 deposit tx hash
go run ./deposit-hash -rpc https://eth.merkle.io -tx $L1_DEPOSIT_TX_HASH
```

## Relaying the Withdrawal from L2 to L1
This step initiates your withdrawal on L1. This step requires a proposer to have proposed an output which includes your withdrawal. Proposals occur about once every hour.

```bash
git clone https://github.com/base-org/withdrawer
cd withdrawer

export L2_TX_HASH=... # Take from the deposit-hash command
export L1_RPC=https://eth.merkle.io
export L2_RPC=https://mainnet-readonly.unichain.org
PORTAL_ADDR=0x0bd48f6B86a26D3a217d0Fa6FfE2B491B956A7a2
DGF_ADDRESS=0x2F12d621a16e2d3285929C9996f478508951dFe4
export PK=... # L1 private key. Can also use a ledger.

go run main.go --withdrawal $L2_TX_HASH --rpc=$L1_RPC --fault-proofs --l2-rpc=$L2_RPC --portal-address=$PORTAL_ADDR --dfg-address=$DGF_ADDRESS --private-key=$PK --network=op-mainnet
```

## Finalizing the L1 Withdrawal
After 7 days, run the withdrawer command again to finalize the withdrawal.

```bash
cd withdrawer

export L2_TX_HASH=... # Take from the deposit-hash command
export L1_RPC=https://eth.merkle.io
export L2_RPC=https://mainnet-readonly.unichain.org
PORTAL_ADDR=0x0bd48f6B86a26D3a217d0Fa6FfE2B491B956A7a2
DGF_ADDRESS=0x2F12d621a16e2d3285929C9996f478508951dFe4
export PK=... # L1 private key. Can also use a ledger.

go run main.go --withdrawal $L2_TX_HASH --rpc=$L1_RPC --fault-proofs --l2-rpc=$L2_RPC --portal-address=$PORTAL_ADDR --dfg-address=$DGF_ADDRESS --private-key=$PK --network=op-mainnet
```

## Submitting Arbitrary Transactions from L1
You can perform arbitrary contract calls (e.g., swaps) on L2 via deposit transactions. To create a deposit transaction on L2, call the Optimism Portal Proxy Contract:

```bash
cast send $PORTAL_ADDR \
    "depositTransaction(address _to, uint256 _value, uint64 _gasLimit,bool _isCreation,bytes memory _data)" \
    $TO $VALUE $GAS_LIMIT false $CALLDATA \
    --rpc-url $L1_RPC_URL \
    --private-key # or other cast wallet options
```

For example, to perform a swap on a fork of a Uniswap v2 pool on L2 using this method you can:

1. Use the Uniswap v2 SDK to generate the required calldata for the swap (see docs [here](/docs/sdks/v2/guides/swapping))

2. Submit the calldata from step 1, to the `$DEX_ADDRESS` of the v2 fork:

   ```bash
   cast send $PORTAL_ADDR \
       "depositTransaction(address _to, uint256 _value, uint64 _gasLimit,bool _isCreation,bytes memory _data)" \
       $DEX_ADDRESS \
       0 \
       $GAS_LIMIT \
       false \
       $CALLDATA \
       --rpc-url $L1_RPC_URL \
       --private-key # or other cast wallet options
   ```

3. If you use this method to swap back into ETH on the L2, you can withdraw the resulting ETH using the methods outlined above.