With firmware versions V2.2.0 (Multi-coin) or later, you can set Polkadot.js as a watch-only wallet that functions as the companion app for Cobo Vault Essential or Pro.
Preparation:
1. Firmware version V2.2.0 (Multi-coin) or later running on Cobo Vault Essential or Pro. (Upgrading Firmware)
2. Setup your Cobo Vault. (Getting started in 5 steps)
3. Polkadot.js: https://polkadot.js.org/apps/#/explorer
Pairing a Cobo Vault with the Polkadot.js
1. Touch the Menu icon -> [Watch-only Wallet] on the Cobo Vault device.
2. Select [Polkadot.js] and touch [Confirm] -> [√].
3. Touch [Display QR Code of DOT].
4. Visit Polkadot.js: https://polkadot.js.org/apps/#/explorer. Click [Accounts] menu and click [Accounts].
5. Click [Add via Qr] and scan the QR code of DOT displayed on the Cobo Vault.
6. Set the name of the DOT account and click [Create]. DOT account created!
7. Touch [Done] -> [Display QR Code of KSM] on the Cobo Vault.
8. Click [Add via Qr] on Polkadot.js and scan the QR code of KSM displayed on the Cobo Vault.
9. Set the name of the KSM account and click [Create]. KSM account created!