Somehow my NVG 510 broadband light started blinking red a couple of time in the last few days. I've been wondering why and I think I have the answer now.

In most cases it may just be that the broadband signal disappears for too long and the modem disconnects.

However, in my case, I think it was because they made an upgrade (a push!) on the modem because a few things do not work as expected anymore. (i.e. I cannot access the nsh shell anymore...)

Whenever software is upgraded, the likelyhood that you have to reset the whole thing is very high. I had to restart twice and even after that, the broadband light was still blinking red, even though I could connect to the Internet and upload / download at will (and full speed it seems.)

To fix the problem for good, I turned off the modem (disconnected) and turned it back on. Now the broadband light is again solid green as expected.