Steps to use Neuron as a cold wallet to circumvent buffer limit of Ledger

This guide is for users encountering the error Ledger device: UNKNOWN_ERROR (0x9405). The solution involves installing a custom version of Neuron on an offline computer, importing the Ledger’s recovery phrase to create a cold wallet for signing transactions.

Requirements:

1. Backup of the Ledger recovery phrase.
2. An offline computer.

Steps:

1. Find an Offline Computer
   Locate a computer that is either offline or has not been connected to the internet and has no unknown software. Disconnect it from the network.

2. Install Neuron
   Transfer the Neuron installer(https://github.com/nervosnetwork/neuron/issues/3285#issuecomment-2541654181) to the offline Computer for installation. Install Neuron and import the Ledger recovery phrase/mnemonics so we have an offline wallet, which is called cold wallet.

3. Prepare the Transaction on an Online Computer
   On the online computer, complete synchronization with Neuron and initiate the desired transaction. In the transaction confirmation dialog, choose to export the transaction and save it as a file.

4. Sign the Transaction with Cold Wallet
   Transfer the transaction file to the offline computer using the external device. Use the cold wallet Neuron to sign the transaction by navigating to Menu => Tools => Offline Sign. This will generate a signed transaction file.

5. Broadcast the Signed Transaction
   Transfer the signed transaction file back to the online computer. Use Neuron’s Menu => Tools => Broadcast Transaction function to submit the signed transaction.

6. Cleanup Process

   1. Recommended: Generate a new Ledger wallet and stop using the old wallet.
   2. If the old wallet will be used further: Delete Neuron and all wallet records from the offline computer. Steps to clear Neuron and wallet will be appended in the comment.

No documentation file or entry point is named. Start by locating Neuron’s existing wallet documentation and compare its conventions with this six-step offline-wallet workflow, including the Menu => Tools => Offline Sign and Broadcast Transaction paths. Done means the guide is placed in the appropriate documentation location and its Ledger, recovery-phrase, offline-signing, and cleanup instructions are reviewed for accuracy.