The unfixed-info.bin file is a . It is not used directly to sign data. Instead, it is used to derive Amiibo-specific keys through a key derivation function (KDF). These derived keys are then used for two main operations:

: Contains permanent information unique to the physical piece of plastic, such as the chip’s unique hardware identifier (UID) and the internal character ID code.

: Contains writable information that changes depending on player interaction, such as the custom Amiibo nickname, the owner’s Mii data, game progress, and character statistics (e.g., training data in Super Smash Bros. ).

The file is a specific data component primarily associated with the Mifare Premium (Amiibo) emulation community. If you have encountered this file, you are likely venturing into the world of backing up or spoofing NFC tags for gaming consoles like the Nintendo Switch, 3DS, or Wii U.

A: Without it, you cannot encrypt new Amiibo data. Many tools, including TagMo, will fail to write or load any Amiibo data until you re-import the key file. You will need to download it again from your backup or from a community source.

To get started, you will need to place three types of files on your Android device (typically in a folder like Downloads or a dedicated Amiibo folder):

In 90% of cases, unfixed-info.bin is a temporary file and can be deleted without consequences.

For those interested in the raw technical details, this section explains the actual cryptographic processes.