Another Ethernet Connection Problem

I did search on this before posting, but it seems other folk's problems were due to using repeaters or bridges. I'm just doing a plain old connection to my router. I just got this unit after frying my old one using the wrong power supply, but my old one did work fine with ethernet.

Wifi works fine with this one, but it doesn't recognize the ethernet connection. I tried the usual things: factory reset; reboot router; tested ethernet cable (same one from before anyway); tried different port on router; downloaded latest firmware. Firmware is now 7.7.3. When I first booted this up after unboxing, the screen showed 'enhanced digital output'; it doesn't show that now probably due to the firmware update. I contacted the seller, and he ONLY used it with ethernet, so it was working for him. Btw, this unit is VERY clean and came with original packaging...well taken care of.

Any ideas? With newer firmware, is there an extra step needed? I read in some other posts about DHCP issues, but not sure if that applies to me with this very basic connection, and I didn't have to do anything special before. I will say that the plug on the cable seems to fit rather loosely into the jack on the SBT, but even if I press and hold it in firmly, still no connection.

Thanks in advance for any advice!