Chapter 2: ethash no longer supported

[carlos-granados]

The latest versions of Geth do not seem to support ethash, so this needs to be removed from the initial genesis.json file like this:

{
  "config": {
    "chainId": 9999,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": 0,
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0
  },
  "nonce": "0x0",
  "timestamp": "0x62272fde",
  "extraData": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "gasLimit": "0x47b760",
  "difficulty": "0x80000",
  "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x0000000000000000000000000000000000000000",
  "alloc": {},
  "number": "0x0",
  "gasUsed": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "baseFeePerGas": null
}

Otherwise you will see this error:
Fatal: Failed to register the Ethereum service: ethash is only supported as a historical component of already merged networks

If you have already initialized your geth database you may still get this error even if you remove the ethash data from your file and run the init command again. If that is the case, run this command:

geth --datadir ./ removedb

And then the init command again