Two days ago, after Apple refused to replace my iPhone 3G for WiFi failure due to visible liquid damage, I bought an iPhone 3GS. Today, it failed, crashing and turning off while the startup Apple logo was still on the screen. Connecting it to a computer produced the same results.
I brought it in to my local Apple Store, where they verified that it was indeed busted. However, after attempting to restore, they told me that it was throwing error code 6, which apparently indicates third-party (hacked) software on it. After informing me, the Genius told me that if this were to happen again, they wouldn't replace it—and were marking the case file to say so.
The issue: I didn't hack my phone.
Yesterday, however, I did update the iPhone's software from 3.0 to 3.0.1. Could something have gone wrong with the upgrade process, somehow surviving whatever checksums the installation runs it through but leaving it in a broken state? I'm not sure of standard iPhone upgrade procedure, but I thought that any update would require a complete restore of the phone. However, after the update, all my data was present without any restore necessary. Maybe it silently did restore it, but I don't know.
Whatever the cause, Apple is assuming that error code 6 means a hacked phone, but based on my experience it doesn't. If it didn't involve a threat not to replace it next time, I wouldn't care, but if they're basing their replacement policies on a flawed indicator, I'm worried for the next time a routine update goes wrong.