I also updated recently. I have had some problems after the upgrade. I have contacted Zyxel. They have answered me quickly and professionally. The solution is to reset the Nas. I have reset using the reset button. The problems have disappeared and now, the NAS does not behave erratically. Sorry for my level of English. I am using a translator. Thank you.
I have recently upgraded the NAS540 to firmware V5.20(AATB.0) and I have some issues.The first one is that I can't find in the new interface how can I move files from one share/location to another like it was possible in the old firmware in "Shares". The second problem is that when I stream movies to my Samsung TV, the Twonky media server (I suppose) is causing the NAS to disconnect and the web interface to freeze. Basically the NAS becomes unaccessible and I have to restart it manually to get it working again. This issue happens randomly, sometimes after 15 min. of playing, sometimes just immediately after I play the movie. The message that I on the TV get is "No network connection", then the NAS freezes. I checked the cables in the switch and they are ok (I first assumed that it was a network cable connection problem).
Can you please help? Eventually, if I can't make it work, is it possible to downgrade to firmware V5.11(AATB.3)C0.