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Firmware updates keep your Trezor secure and compatible with the latest features, but occasionally an update can stall, fail verification, or leave your device in an unexpected state. This guide walks you through the most common firmware problems and exactly how to fix them — without losing access to your funds.

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Device Stuck in Bootloader Mode

Bootloader mode is a special low-level state your Trezor enters to receive firmware. You’ll recognize it by the “BOOTLOADER” text displayed on the device screen, sometimes accompanied by the Trezor logo and firmware version information. Your device may enter bootloader mode automatically during an interrupted update, or you may have triggered it manually. Either way, here’s how to proceed:
  1. Unplug your Trezor from the computer.
  2. Hold down the button on your device (for Trezor Model One, hold both buttons simultaneously).
  3. Reconnect the USB cable while continuing to hold the button. Your device will re-enter bootloader mode intentionally — this is normal.
  4. Open Trezor Suite on your computer. It will detect the device in bootloader mode and prompt you to install or reinstall firmware.
  5. Follow the on-screen instructions to complete the firmware installation.
If your device is stuck and does not respond to button presses, try a different USB cable and port before repeating these steps.

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Firmware Update Failed

A failed update typically leaves your Trezor in bootloader mode, ready to try again. Don’t panic — your funds are safe as long as you have your recovery seed.
1

Disconnect your Trezor

Unplug the device from the computer completely.
2

Restart Trezor Suite

Fully quit Trezor Suite and reopen it. This clears any cached connection state that may have contributed to the failure.
3

Reconnect your device

Plug your Trezor back in. Trezor Suite should detect it in bootloader mode and display a firmware install prompt.
4

Attempt the update again

Follow the on-screen steps to reinstall the firmware. Make sure you stay on a stable internet connection throughout the process and do not unplug the device until installation is confirmed complete.

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Firmware Verification Failed

Every firmware file Trezor Suite installs is checked against cryptographic signatures produced by SatoshiLabs. This verification step ensures that the firmware is genuine and has not been altered. If Trezor Suite displays a firmware verification failed error, do not proceed with the installation. This message means the firmware file did not pass the signature check, and installing it could compromise your device’s security.
Never install firmware from sources other than Trezor Suite. Only official firmware signed by SatoshiLabs passes Trezor’s cryptographic verification. Firmware from third-party websites, forum posts, or unofficial tools may be malicious and could expose your private keys.
If you see this error:
  • Make sure you downloaded Trezor Suite from the official source at trezor.io/trezor-suite.
  • Check that your internet connection is stable and retry — a corrupted download can occasionally cause a false failure.
  • If the error persists, contact Trezor Support at trezor.io/support.

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Firmware Downgrade

Downgrading to an older version of firmware is generally not supported on Trezor devices. Trezor Suite will warn you if you attempt to install a version older than what is currently on your device. Proceeding with a downgrade, if it is permitted at all, will wipe your device — all data stored on the device will be erased. You can restore your wallet afterward using your recovery seed, but make absolutely sure you have your seed written down and accessible before attempting any downgrade.

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Unknown Firmware / Unofficial Firmware Warning

If Trezor Suite displays a message indicating “unknown firmware” or “unofficial firmware detected”, it means the firmware on your device was not signed by SatoshiLabs and cannot be verified as genuine. This warning is most common on:
  • Second-hand Trezor devices that were modified by a previous owner.
  • Devices used for development or testing with custom firmware builds.
If you purchased your Trezor new from an authorized reseller and see this message, treat it as a serious security concern. Do not enter your PIN or recovery seed on the device. Contact trezor.io/support immediately with your purchase details. If you bought the device second-hand, wipe it and reinstall official firmware via Trezor Suite before using it with any real funds.
For persistent firmware issues that aren’t covered here, visit the Trezor Support portal at trezor.io/support or ask the community on the r/TREZOR subreddit. The community forum is especially helpful for device-specific edge cases.