On this thread I will list all Valid Product Codes for each Phone Type which still have active Flash File Links for NaviFirm+.
About downloading using product codes, you can actually do it yourself for free via NaviFirm here:

Download NaviFirm+ Here:
Symbian Toys - Software NaviFirm+ to dowload the firmware of your Symbian smartphone

It is a VERY USEFUL Software so I would Suggest Donating 3 EUROS For It so you can get FULL FUNCTIONS.

If you are still not ready to pay for 3 EUROS Donation, you can still use it for FREE via following 2 simple Steps.

Step 1. Click Cancel (or Click Donate if you want FULL ACCOUNT)

Step 2. Enter Product Code, then Download!

So Here are the valid Product Codes (which still have active firmware links).

Lumia WP8.1 Series:

Lumia 530
Lumia 630
Lumia 730
Lumia 735
Lumia 830
Lumia 638
Lumia 930
Lumia Icon

Lumia WP8 Series:

Lumia 1320
Lumia 1020
Lumia 928
Lumia 925
Lumia 925T
Lumia 920
Lumia 920T
Lumia 822
Lumia 820
Lumia 810
Lumia 720
Lumia 720T
Lumia 625
Lumia 620
Lumia 630
Lumia 521
Lumia 520
Lumia 520T

Lumia WP7 Series:

Lumia 900
Lumia 800
Lumia 800C
Lumia 710
Lumia 610
Lumia 610C
Lumia 510
Lumia 505

Asha Phones:

109 / C1-02i

Other Phones: