I don't know much about DSL modems but the only thing that really makes sense given the electronics and the 15 minute timing is that they don't want you to pull

I don't know much about DSL modems but the only thing that really makes sense given the electronics and the 15 minute timing is that they don't want you to pull the network plug out during an initial firmware update. One would hope that this wouldn't be as fatal as they suggest since the network could disappear suddenly for any number of reasons that aren't limited to physical line disconnection.