Does jailbreaking void warranty?

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.

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 ℹ 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 ,

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.