Of all the problems, the most widespread is simply the tendency for third-party software to crash, including at times on launch -- a problem that participants in Apple's support forums notice is absent from Apple's own built-in applications.
In many cases, users are able to resolve some of the problems by reinstalling apps or resetting the iPhone, though at least some caution that the problem gradually reappears over time and isn't simply a byproduct of their early state.
"At first, it was just a couple of free applications which all worked for the first few times, then suddenly stopped working," one user says. "Deleting and re-downloading them fixed the issue but [the problem] came back, eventually."
Other problems, however, are more immediately troubling even on stock devices. A large number of owners observe that the iPhone 2.0 software is suffering from interface lag where the response to a command follows well after the actual input. While resetting can again temporarily fix the problem, the issue is widespread enough to affect both old and new iPhones and is always gradual, which leads some to believe a memory leak is present and sapping away at available performance over time.
And for more users, the hardware itself is becoming a noticeable problem. Early adopters of iPhone 3G are now complaining of echoing audio on their side of calls when paired with a Bluetooth audio system, particularly in cars. The feedback doesn't occur on the receiving end but is known to be tied to the device itself, as fully updated original iPhones don't suffer from the echo.
BMW drivers in particular are suffering from an apparent flaw which refuses to sync contact data over Bluetooth with their phone integration systems, with multiple 2006 and newer vehicles refusing to show contacts through their iDrive interfaces or to properly identify an incoming call. Some Land Rover SUVs also appear to suffer the flaw, though some note the problem also crops up in first-run iPhones using 2.0 firmware while some with new software or phones have no problems at all.
GPS mapping also proves to be unreliable or even non-functional, according to some reports. At its most basic level, some find the device locating itself in Google Maps well away from its actual position -- in one case, claiming a British owner was located off the coast of Canada. More serious instances see users needing to reset the iPhone to invoke GPS or, in the most extreme circumstances, receiving no lock whatsoever. AppleInsider itself can confirm at least periodic GPS issues.
A handful of problems are independent of wireless, including an unresponsive tilt sensor and the refusal of many in-car audio kits to charge while playing, though the latter is described by iLounge as part of a hardware change that no longer supports legacy docking systems that deliver power over a FireWire interface rather than USB.
Two reports (1, 2) also note the ringer volume resetting regardless of individual preferences.
For all these initial complaints, Apple is nonetheless showing signs that it's addressing problems soon. Those same BMW drivers complaining of contact sync have been contacted by Apple with hints that the company is aware of a problem it intends to resolve.
Website logs at multiple websites, including AppleInsider, also reveal Apple working on an iPhone 2.0.1 update that may fix one or more of the outstanding issues upon its release.