Given Apple’s recent guidelines stating that developers must not mess with hardware controls for fear of confusing users, it’s a pity to discover Apple’s killed the screen rotation lock on the iPad. Numerous sources, including The iPad Guide, state that iOS 4.2 changes the lock button to a mute switch.

Apple’s argument will probably centre on hardware consistency, rather than legacy consistency—the iPhone 4 uses its equivalent button for mute, but I think Apple’s making a mistake. On a phone, the need for muting is common; on an iPod touch—a very portable mobile system—one might make a similar argument. However, on the iPad, muting is not such a common requirement, but the screen rotation lock is regularly used, especially in-app, notably in browsing environments (Safari, Instapaper, Reeder, etc.) and when reading electronic books.

At present, you can lock the screen rotation temporarily, whenever you need to, moving the iPad in and out of the locked-screen state as and when required. All this needs is the click of a button. As of iOS 4.2, the process will change to match that on an iPhone or iPod touch:

1. Double-click the Home button, to access the multitasking bar;
2. Swipe right to access controls;
3. Locate and tap the rotation lock.

Even for seasoned users, this is ungainly, awkward and time-consuming. Worse, for newcomers to the platform, these controls are twice hidden: not only do users need to know that the multitasking bar exists, but also they need to be able to find the controls by swiping to them. I suspect that many will never see them, reducing the usability of the iPad. (For muting fans, it’s also worth noting that the iPad currently provides fast access to mute by click-holding the volume-down setting of the volume rocker switch.)

I hope Apple provides some kind of option for users regarding the functionality of the soon-to-be-mute button. Losing the rotation-lock option by default wouldn’t bother me in the slightest if I could get it back with a quick trip to the Settings app. Sadly, this isn’t the way Apple rolls, and so I guess we’ll all be waving goodbye to a great piece of iPad functionality come November.