Since I asked a lot of question on this forum I would like to share the answers with everybody and maybe help them.
NOTE: Please don't post any replys as I want to keep the post clean and room for updates, send me a PM if you have and idea or any fails that I made in this post, if this post helped you don't post hit just the thanks button. Cheers.
Current list of questions with answers(will be updated):
Why would I want to root my phone?
Is rooting worth the trouble?
Is rooting illegal?
Will I have any customer support?
Is it dangerous?
Isn't rooting a complex and difficult process?
Will I still receive operating system updates from my carrier?
Application updates?
What if I want to un-root my phone?
Do I run the risk of bricking my phone?
Could my phone overheat and explode?
Why would I want to root my phone?
Everything in a Linux system is a file, or is treated as a file. Since Android runs on top of Linux, it acts the same way. Most of the files you will need to access or change are available to you without having elevated permissions. "Most" being the key term here. When you want to do things that affect or change the core software of your device -- like updating the version of Android on your phone, or adding a nice piece of software from another device -- you'll have to do it as root. Dream and Magic users have been running Eclair on their phones for a good while now, and it’s because they have rooted their device. Rooting also gives you access to some handy software that you couldn’t use otherwise. Things like a complete system backup or ad blocking software require you to root your device. Don’t root your phone just for the sake of rooting your phone, but if you come across something you feel you could use or would like to have, then consider it. You'll find that the open source community is usually pretty helpful and encouraging new people to do new things is common. And when you get to the point where you can lend a hand to the new folks, pay it forward.
Is rooting worth the trouble?
The answer is a resounding yes. The phone is faster than it has ever been, the battery lasts longer, and have all kinds of new features, including free wireless tethering and notification-bar widgets. Rooting your phone is generally a fairly quick process, though the complexity depends on your specific situation. Once you're rooted your handset, you can begin installing apps (many directly from Android Market) that will take advantage of your handset's new capabilities. Installing custom ROMs (replacement operating systems) built by hackers is a longer, more involved process , and generally involves your wiping all the data from your phone, but even that is worthwhile.
Is rooting illegal?
Nope. You bought the phone, it's your equipment, you own it, and you can do what you want with it. No one is going to come and get you, and your service provider will not cancel your contract. In fact, the U.S. federal government recognized the legality of rooting a phone in July 2010.
What you will do, however, is void the warranty on your device. If you don't want to live without a warranty, rooting isn't for you. Personally, I finally decided to take the plunge when I realized that the potential benefits outweighed the potential consequences. My phone was becoming slow and buggy, with lots of force-closes, and I was just about eligible for an upgrade anyway.
Will I have any customer support?
Rooting can be daunting because there is no toll-free number you can call for help, and no governing body to which you can turn for definitive answers. But the collective process of rooting phones and creating custom ROMs has engendered cool and supportive communities. The user-generated forums out there contain a staggering amount of information; the CyanogenMod forum has offered answers to almost all of my questions, as has the XDA Developers forum, but you can find many more. No matter your question, the forums most likely already have threads that can answer it. If you really can't find anything, you can always start a new thread to ask your question. If you think you've really mucked things up and you need immediate help, many IRC chat channels specialize in support for rooters. (Download an IRC client on your computer and head to irc.freenode.net, where the channels #android and #android-root are particularly helpful.)
Is it dangerous?
It can be, It might, and Yes. By not allowing access to the superuser account, the manufacturer and your carrier have basically protected you from doing things that change the system and make it unusable. All it takes is one wrong keystroke to turn your shiny new Android phone into a plastic and metal brick with no connection. Most times this is recoverable, but not always. You have to decide how capable you feel you are, and how well written the instructions you’ve found seem to be. Nobody will blame you if you decide against the risk, especially your cell carrier. All major carriers and manufacturers plainly state that altering or using unapproved software voids your warranty, and rooting falls into that category. While that seems a bit harsh, they need to be able to support the products they sell. For that to happen, they need to know exactly what’s running and what it’s doing.
Apps that run as root need a little further consideration. You need to have a level of trust in the person who wrote the app first and foremost. Does the developer have other software available? Do the user comments (for Market apps) have anything that raises a red flag? Do the requested permissions seem a little odd? These are all questions you need to think about before you allow something to run as root. For a further level of security, think about installing an application that warns you anytime something tries to run as root. SuperUser Whitelist is a great little app that does exactly that. If you decide to go on and root, ask users with the same device as you for a link to a version of SuperUser Whitelist that works with your firmware. Once installed, anytime something wants to run as root, the app intercepts and asks if you would like to allow it. You’re given the choice to accept, decline, or grant the app in question full privileges each time it runs.
One last thing to touch on here. Many custom ROMs include some sort of SSH server. This can be a wonderful tool, or it can get you in hot water. This is what caused the whole “Rick-Roll” episode with the latest iPhone jailbreak. The server sits and waits for an outside connection, and if that connection provides the right password full control of the device is turned over. In the case of the iPhone, users never bothered to change the default SSH password for root. A clever (or devious) group of users simply scanned for servers listening on the correct port, then attempted to sign in as root with the default password. Lesson learned, but this is easy to prevent. Ask other users of the ROM or firmware you’re thinking of flashing if there is a server listening, and if so how to disable it or change the default password.
Isn't rooting a complex and difficult process?
Yes and no. It really depends on what model of phone you have. On many phones (such as the Nexus One, Motorola Defy, or EVO 4G) the process is incredibly easy: You can download an app such as Simple Root, Universal 1-Click, or Z4root that will safely root your phone with a single click. Those apps are no longer available from the Android Market, but you can find them online with a simple search and install them onto an SD Card.
It is important to note that different approaches will work for different phones. For example, Z4root will work on many Android phones, but it won't work on most HTC models. Some rooting apps will work on an early build of Android 2.2 (Froyo), but will not work on later builds (though more and more apps are being released for that now). Rooting is phone/OS specific, so make sure to check that the root tool you're considering is compatible with your phone. For other models, rooting may take much more work. You might be required to connect the phone to your computer and enter some lines of code in a terminal utility.
Fortunately, more and more root apps do not require you to hook up your computer and get in that deep. Do some research as to what is required for your setup, read some step-by-step guides, and be honest with yourself about how comfortable you would be trying to follow the directions. If it feels like you'd be in over your head, it's probably best to avoid rooting.
Note that generally rooting is even tougher to do if you use a Mac, as most of the software for doing this sort of thing is written for Windows or Linux.
Will I still receive operating system updates from my carrier?
Maybe. More than likely if you’ve just rooted your phone so you could have access to the full file system and haven’t drastically changed things, the phone will still pass your carrier's checks and upgrade. If you’ve delved deeper and really customized your device, count on not being able to upgrade. Carrier updates were designed to work with the original software, so they need to be sure that’s what the phone is running. Again, this is for your own good. T-Mobile or Verizon can’t offer technical support for things they haven’t trained their technicians on, and if you flash a carrier approved update over custom software it’s probably not going to work.
The good news is that failing the checks the carrier does during an update won’t cause any damage to your phone. The update will just quit and you’ll be back where you started. Then you can decide if you would like to un-root and upgrade or take another path. The worst case scenario is that the phone passes the carriers checks, updates, and then things get broken. That’s pretty unlikely, but possible. If that would happen, you won’t be alone. Everyone in your situation will scramble to their favorite Android user forum and hopefully a work around can be found.
Note - a carrier update may also break the ability to root the device and a new method will need to be found. Any discussion of upgrading and root needs this mentioned as well. Most folks who root and decide to install a custom ROM wait for the ROM developer to provide an update that includes any bug fixes or new capabilities of the carrier update.
Application updates?
Yes. While it’s not being used, the program that allows permissions to be upgraded just sits and does nothing. Normal applications won’t even be aware it’s there, and applications that use it expect it to be there. Application updates, whether they are from the Market or other third parties will still install as normal.
What if I want to un-root my phone?
It depends on the model of your phone. Some are ridiculously easy to revert, some not so much. This is the most important question you can ask before you dive in and root your phone. Usually the website you found the method to root your phone will also have a discussion about un-rooting and going back to stock firmware. Take the time to find and read this information so you’re aware of just how difficult it’s going to be to go back. Pay close attention and create backups when recommended while you’re rooting your phone, as these may be needed to go back. I’ve not heard of any device that can’t be restored to factory firmware provided the original was backed up properly as recommended during the rooting process. The most important thing to always remember is to ask for help. If you do find yourself stuck without a backup or a working phone and need to roll back, ask for advice. Our forums are full of fine folks from all walks of life, and the majority are more than happy to help. There’s a good chance you’re not the first person in that situation and a solution has already been worked up!
Do I run the risk of bricking my phone?
This is one of the Internet's favorite bogeymen. "Bricking" is the idea that if you try to tinker with root access, you'll mess something up so it becomes completely unusable, and you'll essentially turn your phone into a paperweight. While that's certainly not outside the realm of possibility, the good news is that Android phones are generally very hard to brick. Yes, even the Droid X, which was purported to be the "unrootable" phone, has been safely rooted for quite some time (Z4root reportedly works with the Droid X).
If you do get caught in a boot loop, you may have to connect your phone to your computer and rewrite some code, but if you are patient and willing to do some more reading, you will almost always be able to find a way to at least restore your phone to its original state (read more on where that help comes from in the next section).
A common mistake that actually will lead to a bricked phone is running out of battery power in the middle of trying to install a custom ROM. The operating system only half installs, and that really is tough to fix. So always make sure that your battery is full before you install a new OS or ROM.
Also, just because a phone is rootable does not mean you can install any custom ROM you want. Differerent ROMs will work for different phones. Even the extremely popular CyanogenMod works for many phones, but certainly not all, so do plenty of research to make sure your phone is supported before trying to install a custom ROM.
Could my phone overheat and explode?
One of the major incentives to root your phone is the ability to overclock your processor to gain more speed (or underclock it to extend battery life). My phone has gotten considerably faster because of overclocking. When you overclock your processor, though, it will get hotter. If you try to push your phone too far and you don't set any fail-safes (a maximum allowable temperature in the overclocking utility), then you could burn out your processor. However, it is very easy to set safety thresholds to ensure that you don't do that.
SetCPU, the most popular app for overclocking or underclocking, allows you to set up various profiles.
Reading the rooting forums will give you plenty of advice on how far you can push your specific device and maintain stability. It pays to do some experimentation: Different phones behave differently, even if they're the same model.
Sources: androidcentral.com, pcworld.com