hi,
i have dir855, bought in Italy and replaced 2 times directly from DLINK by RMA procedure.
After firmware update (actually i'm using 1.22NA), the router was stable with wired connection and 2.4Ghz wireless connection.
The problem is the 5Ghz connection; the signal is poor and when, for example, i try to access into my photo folder (resident on my NAS) and i launch the Microsoft Photo viewer, the router automatically restart and i lose the connection.
WHY?  
 
 
This is my config.txt
Firmware Version: ver1.22NAb04 
Firmware Date: 2010/01/21 
ipVersion(Date): 7.6.1b0159 (2010, Jan 18) 
ipOS SDK Version: 7.6.3 P (1134) 
WAN MAC: 
LAN MAC: 
WLAN MAC 0: 
WLAN MAC 1: 
Wireless Region 0: 0x0E 
Wireless Region 1: 0x0E 
Radio 0: 2.4GHz Band 
    SSID: xxxxxxx
Radio 1: 5GHz Band 
    SSID: yyyyyyyyy
SubVendorDeviceID 0: 0x2081 
SubVendorDeviceID 1: 0x2082 
Wireless Domain: 0x37 
Firmware Notify URL: http://wrpd.dlink.com.tw/router/firmware/query.asp?model=DIR-855_AX_NA 
Firmware Global URL: http://wrpd.dlink.com.tw/router/firmware/DIR-855/Ax/NA/DIR855A2_FW121NAB04.bin 
Checksum: 0x042C55E4 
Use non DFS channel only: Enabled 
This version is Release version 
USB_IP/K=Disable 
USB_IP/S=Enable Version 1.1.1 
WLAN 0 Channel List: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 
WLAN 1 Channel List: 36, 40, 44, 48 
HW Ver: A2 
tks
Freeman