Most likely something went wrong during the firmware update and your Trezor got wiped (this is a security feature). There is no need to worry, all you need to do now is run a recovery process using your recovery seed words. You can find a manual on how to recover your wallet by following this link.
Once this is done you should be able to access your wallet with all your coins.
Please, note that if you were using passphrase protection prior to the firmware update then you need to re-enable it in the Advanced menu tab.