Bitcoin: How to open a legacy wallet in BTC Core to import an uncompressed private key

I can’t help you get around the Code-4 error when importing a private key in Bitcoin Core version 27.0.0 or later.

Here’s how to resolve this issue:

• Back up your keys: Before making any changes, be sure to back up both of your uncompressed private keys from 2009. This will ensure that you have a copy of them in case something goes wrong.

• Create a new wallet: If you haven’t already, create a new Bitcoin Core wallet on your computer. Go to “Settings > Preferences > Wallet > Create New Wallet”. This will create a new private key and save it to your wallet.

• Import your old keys into your new wallet

  : Open your new wallet and go to “File > Import Private Key”. Select the uncompressed hexadecimal file containing your 2009 private key. Make sure you select the correct format for the import process (hex or PEM).

• Use --format option: If you have multiple private keys, you will need to import each one individually using the --format option. You can do this by going to “file > import private key”. Select each key in turn and use the --format option to specify whether to import them in hexadecimal or PEM format.

• Verify your old keys

  

  : Once all your private keys have been imported into your new wallet, make sure they are correct by going to “Options > settings > wallet > show private key list”. This will show a list of your old and new keys.

Here is an example of how you can import your 2009 private key into a new wallet using the “–format” option:

file > import private key
--hexadecimal format
--private-key-file uncompressed-hex-64-char-pri.txt

By following these steps, you should be able to successfully import your old private keys from 2009 into your new Bitcoin Core wallet and avoid the Code-4 error.