I also have the Nokia 521 with the latest "amber" FW update 3046.0000.1328.2024. The flip phone-to-mute incoming call function works, but there is no way I can double tap on the screen to wake-up/unlock the phone. Also discovered that the following items are missing/not available:
1. Cannot download the Nokia Smart Camera app...said app is not applicable to this phone. Shouldn't the amber update allow the 521 to use the Nokia Smart app?
Nokia Smart Cam | Windows Phone Apps+Games Store (United States)
2. There is no storage check app available after the 521 amber update. My 520 has this app.
3. There is no incoming caller blacklist.
On the plus side, I was not able to iniate WiFi calling regardless of modem/router/ISP. This amber FW update fixed this problem. This FW update has also allowed me to "ring" and "track" my phone via windowsphone.com. The phone must have access to WiFi or data plan. Be sure to turn "on" Send Apps and Save Phone Location in FIND MY PHONE. Finally, turn "on" the phone's LOCATION to enable GPS tracking (don't need this to "ring" the phone).
TIA,
F