A BSV transaction I sent to myself was replay attacked on BCH. How do I recover my BCH? [closed]

Question

I wanted to empty out an old paper wallet that still had a small amount of Bitcoin Cash and Bitcoin Satoshi Vision. I set up a new Coinomi Wallet (because it has all the bitcoin forks) and sweeped the private key. After making the BSV transaction, the coins on the BCH moved too, without me initiating the transaction. The transactions on both chains have the same transaction hash. However the Bitcoin Cash account of the Coinomi wallet stayed empty. Is there a way to recover those coins?

Answer 1

The BCH are recoverable. They were moved to an BCH-address that is derived from the seed of the Coinomi wallet with the derivation path of the BSV-wallet. This address will not be displayed by default. In order to recover the coins do the following:

First look up the derivation path of Bitcoin SV. You can do this in Coinomi when you click on "add coin" and choose Bitcoin SV. When chosen the gears-icon appears next to the name of the coin. Click on the gears icon and a popup opens with a button "advanced settings". Click on that button and the derivation path will be shown. It should be M/44'/236'/0'

Now, it could be possible to add Bitcoin Cash to your Coinomi with that derivation path. But that was not working for me, maybe because I already had BitcoinSV added with that path.

So I used this BIP39 Tool instead. Warning: The following means to enter your seed into a tool that is potentialy untrustworthy. After doing this I consider this seed as compromised (even though I used an air-gapped computer to do it). You should probably too. I recommend you move all funds from the wallet before you do this and never use this wallet again afterwards.

Anyway. I downloaded the tool to my computer and opened it in my browser. I put in my seed and set the derivation path to the BSV-path (see above). The tool gives you a list of pub/private key pairs. I used the Coinomi wallet to import sweep the private keys (and set the coin to BCH). The second private key had access to the lost BCH and I had them in my Coinomi wallet again.