Q: Does jailbreaking void warranty?

All support (warranty, etc.) ends when an iPhone is jailbroken.

See http://support.apple.com/kb/HT3743

Here's the deal: Some folks have success restoring a jailbroken iPhone back to factory specs., some don't. If you fall into the later category, your warranty/support is voided.

Not all jailbroken iPhones can be restored to factory specs. That's the chance you take.

It may be a late reply but jailbreaking _does_not_ void the warranty unless: ""Apple cannot void an iPhone's warranty unless it can show that a problem or component failure is linked to the installation or placement of after-market item such as unauthorized applications""

Don't see the point of jailbreaking nowadays anyway;

This Warranty does not apply: (a) to consumable parts, such as batteries or protective coatings that are designed to diminish over time, unless failure has occurred due to a defect in materials or workmanship; (b) to cosmetic damage, including but not limited to scratches, dents and broken plastic on ports; (c) to damage caused by use with another product; (d) to damage caused by accident, abuse, misuse, liquid contact, fire, earthquake or other external cause; (e) to damage caused by operating the Apple Product outside Apple’s published guidelines; (f) to damage caused by service (including upgrades and expansions) performed by anyone who is not a representative of Apple or an Apple Authorized Service Provider (“AASP”); (g) to an Apple Product that has been modified to alter functionality or capability without the written permission of Apple; (h) to defects caused by normal wear and tear or otherwise due to the normal aging of the Apple Product, or if any serial number has been removed or defaced from the Apple Product.

as in Jail breaking

Sorry I should have pointed out that quote is from the iPhone specific warranty not the mac or any other Apple |device ,

Makes 0 difference; I have had jailbroken iPhones till 5 and visited apple store/genious bar with issues and they have always been fixed / replaced.

You're not switching chips inside to modify it;

As I said - they may refuse saying whatevertheissueis is software related; then you just have to restore it.

I have been in an Apple Store at the Genius Bar when a tech would not even look at someone's device until the jailbreak was removed. This may be different if they have something like a cracked screen under AppleCare but if it is anything else they can refuse to work on it until the jailbreak is removed. Even if it's faulty RAM or a bad battery that will be covered, they may not look at it until the jailbreak is gone. Of course that could be to the discretion of the tech but I have seen service refused.

That's what I'm saying; they may refuse to work on it; but it doesn't _automatically void the warranty_ on the device. RAM or battery drain may be cause by software issues; so can be understandable.