I found this definition from the code
/**
* The user can't authenticate because the hardware is unavailable. Try again later.
*/
public static final int BIOMETRIC_ERROR_HW_UNAVAILABLE = 1;
Since there's already BIOMETRIC_ERROR_NO_HARDWARE
for the case where the device has no hardware and the definition of BIOMETRIC_ERROR_HW_UNAVAILABLE
has "try again later", it looks like BIOMETRIC_ERROR_HW_UNAVAILABLE
means the hardware is there. It's just not available at the moment. If that's the case, what are the possible causes for this?