Most likely something went wrong during the firmware update and your Trezor was wiped. This is a security feature that is meant to protect your device against physical attacks, for example if an attacker tried to install unofficial firmware on your Trezor device.
However, there is no need to worry. All you need to do now is run the recovery process using your recovery seed phrase.
Please follow these instructions:
Once this is done, you should be able to access your wallet with all your coins (if passphrase protection was used prior to the wipe, please make sure that it's enabled).