I'm on the north side of Chicago and I also had an Altell phone. I brought it to the North/Clybourne store as well as the Irving Park (and like Central I think...pretty west), and the Arlington Heights store and the Lake Cook/Skokie Blvd store. Nobody could flash the phone and Verizon replaced it.
My 7135 is with Verizon. I was directed to a certain level (don't remember what Verizon calls it) of Verizon Wireless store for phone software upgrades.
Such a store is located west of Yorktown near Butterfield & Finley on the Downers Grove/Lombard border. But they said they were unable to do the upgrade, and I didn't push them to experiment on my otherwise healthy phone.
Still looking, though not in a hurry to move to Graffiti 2.