# Raw transaction

## Description

`ERC1820` is a contract that is considered a special case since it requires a few modifications in order to work on VeChain. It is used by `ERC777` so failure in `ERC1820` inevitably results in failure in `ERC777` also. The changes required for `ERC1820` were the following:

1. Chain-tag
2. Contract address passed in constructor

### Chain-tag

The first change that we have to do is change the chain-tag of the transaction creating the contract from 0(?) to 0xF6. Since the contract exists in a compiled form under `openzeppelin-contracts/node_modules/@openzeppelin/test-helpers/src/data.js` we had to change the binary in that file alongside the address. The two lines that were changed can be seen below:

```javascript
const ERC1820_REGISTRY_ADDRESS = '0xb02a08775234755be24ba32da95cf4509cfcee86';
const ERC1820_REGISTRY_DEPLOY_TX = '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';
```

We generated the `ERC1820_REGISTRY_DEPLOY_TX` by using the following [test](https://github.com/freemanzMrojo/thor/blob/test-eip1820/api/transactions/transactions_test.go#L133) in thor to generate the hex string version of the transaction with the new chain-tag. We also had to use the relevant command to query thor to give us the `ERC1820_REGISTRY_ADDRESS`. Once we had that we updated the two lines in the node module.

### Contract address passed in constructor

The last change that we needed to do is in `ERC777SenderRecipientMock.sol` and `ERC777.sol` respectively. In both cases we changed the line that instantiates `IERC1820Registry` by changing to the correct contract address.

```javascript
IERC1820Registry private _erc1820 = IERC1820Registry(0xb02A08775234755Be24Ba32dA95Cf4509CFcEe86);
```

```javascript
IERC1820Registry internal constant _ERC1820_REGISTRY = IERC1820Registry(0xb02A08775234755Be24Ba32dA95Cf4509CFcEe86);
```

With these changes one can deploy `ERC1820` on thor.

## Contracts Affected

| Contract Name           |
| ----------------------- |
| ERC777                  |
| ERC777PresetFixedSupply |
| ERC1820Implementer      |


---

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