There's a bug in curl in 1.2.0 it won't download the firmware. All that's needed is download the firmware on a PC, scp it over to the router and upgrade from there.
We've just discussed the same issue here: New router. Trying to update to 1.9 but it fails (There was an error upgrading the system.)
The solution is easy, no need to do return. If you get replacement router with 1.2.0 you'll be facing the same issue.
