I don 't know, if it helpfull, but maybe it is true, that fingerprint device originally is made by UPEK/Authentec, but you can not control it directly because of Broadcom USH layer?

http://forum.notebookreview.com/dell-latitude-vostro-precision/413346-dell-new-fingerprint-reader-owners-must-read-broadcom-ush-issue-effecting-preciosn-m4400-m6400-latitude-e6400-others-6-print.html says:

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On Dell E-series laptops the fingerprint sensor is connected via proprietary interface from Broadcom and UPEK/Authentec driver cannot communicate with the device at all. The driver cannot see the sensor - it is "hidden" behind the Broadcom chip :-(
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I could REM out a line of code or two in INF file of the fingerprint sensor device
Well, I would love to have a complete information about that ;-) But frankly speaking I don't see any logical reason why to do this. Even if you modify the VID and PID list in the Broadcom driver INF file, it simply cannot start working with the fingerprint reader. It's like if you want modify your video drivers to control your printer ;-) Broadcom coprocessor and our fingerprint sensor are completely different devices, each of them requires a different driver. Furthermore, as far as I know, the fingerprint reader is not enumerated by the system at all.

I went through the whole forum thread and the only guy who was close to some solution was the one who disassembled the fingerprint reader device. If this would be connected directly to the USB (to bypass the Broadcom controller) then the fingerprint reader will be normally enumerated by the operating system and it may work correctly. I deliberately use may, as the firmware of TCEFA1FH is designed for use with Broadcom only - it does not support some of the more advanced USB features (my understanding is that these are primarily related to error recovery). Furthermore the TCEFA1FH requires 3.3V, while standard USB provides 5V, so you will need to use some adapter to change the voltage. For "real" USB applicatons we recommend the TCEFB1. Anyway, I do not recommend you to do such hardware modifications!
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Miroslav Buran
Technical Support Manager
UPEK


Becides http://www.dell.com/support/home/us/en/04/Drivers/DriversDetails?driverId=R214858 says:

Please note: The BCM5880 firmware update process contains 2 protection mechanisms to prevent unauthorized updates.

Protection Mechanism 1: TPM Deactivation.

If the Trusted Platform Module (TPM) on the target computer has ever been activated in the past, in order to update the BCM5880 firmware, the TPM must be set to ON and DEACTIVE in the BIOS SETUP program before the firmware update will run. If the TPM on the target platform has never been activated previously, then this step is NOT necessary.

Protection Mechanism 2: Anti-Hammering.

The BCM5880 is equipped with Anti-Hammering protection that detects large numbers of read/write requests in a short period of time. This mechanism protects against malicious software that attempts to gain access to stored credentials by using multiple retry methods such as dictionary or brute force attacks. If a large number of read/write attempts are detected, the BCM5880 will temporarily shut down to prevent unauthorized access, and a reboot is required. In some instances, starting a firmware update may trigger the Anti-Hammering protection if the BCM5880 has just been recently used. In this case, the firmware update tool will prompt you to power off and then power the system back on, and then proceed with the firmware update.