Forbidden Key Path - Trezor

In some older cases, specific firmware versions (like v2.3.1 for Model T or v1.9.0 for Model One) introduced stricter path enforcement that broke compatibility with certain apps. While keeping firmware updated is generally recommended for security, some users have historically downgraded firmware as a last resort to regain access to funds on non-standard paths. LUKSO error forbidden key path - Trezor Forum

For example:

In a perfect world, a user would generate a seed on a Trezor and only use the official Trezor Suite wallet. In this scenario, the wallet software requests keys based on established standards, and the Trezor firmware happily approves the request because it recognizes the path as valid and intended for the user's specific cryptocurrency. trezor forbidden key path