Hi, I just purchased a second-hand iPhone 4s, only to discover that WIFI doesn't work (can't turn it on) and the battery is drained quickly (8hours on a full change on standby with no usage). Searching the internet, I've found that this is a common problem for 4s phones and is due to bad solder joints on the WIFI chip(s) (wow, Apple, are you STILL doing this - you retired my iMac with exactly the same issue. Grrr!). Apparantly iOS 7+ diagnoses the WIFI chip before enabling it and if something's wrong, it won't. Fair enough, I suppose, except the issue was probably there all along, including while it was under warranty, only you couldn't know. What I'd really want to know is whether the battery problem is associated with the WIFI problem or not. I can live without WIFI and replacing the battery would be fine, but if the battery is drained because of the WIFI problem, that wouldn't do me any good. Does anyone know? Reflowing the solder on the WIFI chip(s) is a solution, but not one I'm eager to perform. The hairdryer/freezer trick is not a substitute. Thanks in advance.