The BIP39 passphrase option is off by default when creating a new wallet. This is on purpose because it is a dangerous feature for new users. The BIP39 is not your normal "send" password, and it's only required when restoring. The extra BIP39 phrase is NOT shown anywhere in-app, and if one forgets it the wallet cannot be restored with just the normal Recovery Passphrase.
It's not possible to "add" a BIP39 passphrase to your current wallets. In essence, "adding" a BIP39 to a recovery phrase is creating a brand new wallet. You must then manually send funds from the old wallet to the new. Read the detailed steps below:
Android and Desktop:
- Back up your recovery passphrase.
- Click on "Settings - Manage wallets"
- Click on the blue '+' button and then "Restore a Wallet" and enter your recovery passphrase, but this time click on the "advanced settings" and check the BIP39 box and enter any phrase or word you like. Make it memorable. Your funds will be irrecoverable if you forget the phrase. You may wish to write it down and keep it safe, somewhere separate from your recovery phrase.
- On the next screen, enter a strong password for transactions.
- Add the wallets you will to use.
You may want to repeat steps 2, 3 and 4 to double-check that you remember the BIP39 and that you can re-enter again correctly. If you do everything right, a new wallet will not be added. Instead you will get a message "A wallet with the same recovery phrase already exists".
- Now it is a matter of transferring your coins to the new phrase. In the wallet with the BIP39 passphrase open the "receive" page of a coin you have.
- Open the wallet which is configured without the BIP39 passphrase, open the wallet of that same coin, and send to the new address (Copied in step 6)
- Repeat steps 6 and 7, one coin at a time until all your funds are on the new addresses.
- Make sure you have your Recovery Passphrase from your device (Settings - Show Recovery Phrase).
- Make a list of the coins you are holding, and if any coins have multiple wallets.
- Go to "Settings - Delete Wallet", then "Restore wallet".
- After entering your phrase, select the "Use BIP39" option at the bottom of the screen and enter your desired BIP39. Make it memorable. Your funds will be irrecoverable if you forget the BIP39. You may wish to write it down and keep it safe, somewhere separate from your recovery phrase.
- Continue with the normal setup and add the coins you noted down on step 2.
- Go to each of those coins' wallets and copy their "Receive" addresses from their "Receive" screen. Use copy-paste or save images of the screen with the QR code. Make it very clear to which coin each address belongs to.
- Click on "Settings - Delete wallet", then "Restore Wallet" once more.
You may want to repeat steps 4 through 7 again, to make sure that you can restore the BIP39 wallet correctly. If you repeat those steps and all addresses are the same, you did everything correctly. Then you can confidently continue following the instructions below.
- Enter your old, original Recovery Passphrase but do not select the BIP39 option.
- After setting a password, select the wallets you noted on step 2. You should see your balances and transaction history as normal.
- Send each coin to the receive addresses you copied in step 6. Take it slow and pay attention to which coin each address belongs to. Do not send the wrong coin to an address! Wait for the transactions to confirm.
- Click on "Settings - Delete wallet" then "Restore Wallet again" one final time
- Enter your Recovery Passphrase and select the "Use BIP39" option. Enter the BIP39 like you did on step 4.
- Enter a strong password on the next screen, then add the coins you noted on step 2.
You should now have all your funds in your new, BIP39 protected wallets. If you want you can create a wallet with a BIP39 immediately during its creation. For that, select "create new wallet" and enable the "advanced settings" when the app shows you your recovery phrase.
The BIP39 passphrase is standard and it is supported on various Bitcoin wallets, but not all. Due to the way it is implemented there is a chance that it would not work if your BIP39 passphrase has composite letters, for example é, å, ώ (they can be interpreted as a single letter or a plain letter + a letter mark). If you want to be 100% sure that you are not affected from this and be cross compatible, make sure you check that you get the same addresses using the recovery phrase tool (it works even offline, just save the page). If you enter a BIP39 passphrase in the tool and you get the same addresses as in your Coinomi account, then you are OK and you will always get the same addresses as long as you enter that exact passphrase.
Final warning, be sure to backup your recovery phrase and BIP39 passphrase somewhere safe, away from your device. It's not possible to restore your wallets if you lose the recovery phrase or the BIP39. You must have both!
Extra tip: for one recovery phrase you can have many "hidden" wallets, each one of them using a different BIP39 passphrase. You can have a single backup for your recovery phrase, and different BIP39 passphrases generating different and independent wallets.