I have 2 N mode access points - a DAP-1522 which runs on 5GHz and a Buffalo (don't remember the model number, maybe GRZ300N?) on 2.4GHz. Both access points use the same SSID and WPA2 with AES encryption (and the same PSK). (Ie this is setup to allow wireless roaming between the 2 access points).
With the previous firmware, the DSM-750 reliably connected to the 5GHz access point, although the signal strength reported by the DAP-1522 is only 50%.
I just updated my wireless DSM-750 to firmware 1.02. I noticed I now get 2 items in the station list with my SSID (where I'm sure there used to be only 1 before). By experimenting I determined that the top item was the 2.4GHz Buffalo. I was able to connect to that with no problem. I could tell which access point I was connected to be which had the flashing lights while watching a movie (I also yanked the ethernet cable out the back to prove the point...)
As I have some 802.11g devices I wanted to get the media player back on the 5GHz band where it used to be. I tried selecting the second station with my SSID, but I just couldn't get it to connect.
The DAP-1522 shows:
Dec 18 00:49:26 [Wireless]4-way handshake success:STA 00:18:E7:51:52:43
Dec 18 00:49:26 [Wireless]Association Sucess:STA 00:18:E7:51:52:43
in the log, but the DSM-750 never managed to make the connection to the DHCP server, and never gets an IP address. The DSM-750 eventually timed out. I tried setting the DSM-750 to static addressing and configured the IP addresses for my network and it still times oud, and if I selected "retry" it timed out immediately instead of waiting the minute or so.
I switched off the Buffalo access point and then the DSM-750 was able to make a connection and is now running OK. (I had tried at least 10 times to connect before, and the failure was "solid", so I don't think it's coincidence that shutting off the Buffalo made a difference). I have since restarted the DSM-750 while both access points were on, and it seems to maintain it's connection to the DAP-1522 now. (One is on 2.4GHz the other 5GHz, so this is not a wireless interference problem, and I didn't have this problem in the previous firmware.)
By the way - this configuration does show one problem. With the wireless settings page it is impossible to tell access points apart, and as the player does not seem to "roam" to the fastest automatically, it would be helpful to be able to tell which is which in the listing. (Wireless configuration on some multi-band D-Link wireless cards shows the band and channel of the access points which would be a nice feature for the DSM-750).