[Nexus 7 (2013) General] Hnk1:
Hello all,

I know there are many people who are curious about android or/and are about their new device. With this in mind, I have decided to give a brief idea about Android and its different aspects. I will use as simple words as possible.

Every highlighted word is a term that is used often at XDA or just refers to the word in FAQs in case you cannot find it.

ANDROID

is an open-source (thus possibilities endless) mobile operating system (OS) based on the Linux kernel and currently developed by Google

With a user interface based on direct manipulation, Android is designed primarily for touch screen mobile devices such as smartphones and tablet computers, with specialized user interfaces for televisions (Android TV), cars (Android Auto), and wrist watches (Android Wear).

ANDROID

is usually based on these four major components:

ROM :

It is the system on which phone works (like windows for PC). Or simply called an Operating System. Can be Custom/Stock. Usually you need a custom or official tool to install/ repair a STOCK rom.

KERNEL

is a part of ROM which is a programmed code that tells the phone how to function in accordance to the ROM & hardware capabilities. It can also be Custom/Stock. Sometimes they are used to enhance user experience, performance, battery life by small changes made to them. Some kernels are specific to ROMS.

DIFFERENCE BETWEEN CUSTOM/STOCK

When you buy your phone/tablet from a retailer, you are on STOCK ROM and STOCK KERNEL. (its from your mobile manufacturer and in this case straight from Google as it is a nexus device. Thus it is called a STOCK ROM/ STOCK KERNEL.

The STOCK ROM & KERNEL is usually an all-rounder to fit most of the users. However, some people are not happy with the limited option available on their devices. As Android is open sourced, and thus easily customized, they want to explore different options by tweaking their devices

In other words, some people like gaming on their devices while other want to increase the battery time, speed, performance etc and the possibilities are very vast as what we want from our devices. Like a person who likes to read books on his device would not care for heavy gaming performance but appreciate if he can get more juice out of his device so he can read more on a single charge.

Therefore, we can say we all need different flavours and thus there is a need for customisation. However, there could be some minor disadvantages too that come with some advantages like overclocking can result in heating and quick battery drain while it increases performance. Also, increased battery life might slow down your device if you are tweaking or under-clocking it too much Therefore, most of the developers try to find the best combination of both performance and battery. However, some custom ROMS/Kernels are developed with specific functions in their core like they might focus only on performance and gaming while other might just ignore heavy gaming and focuses on battery usage. Therefore, it is to your advantage to use your device how you like want it to function according to your preference.

By customisation, we run our devices to our needs and get the most out of it in accordance to how we want to customise it.

SOME CONSIDERATIONS

All devices ROMs and KERNEL are specific. This means stock/custom ROM for every device is specific so you cannot flash a ROM which is made for other device. This can permanently damage your phone. A famous Custom Rom is CyanogenMod which is currently on version 12.1. Although the ROM would be same for many devices, but you can not flash CM12.1 for Xperia M to Xperia M2 etc. In the same way, you can not flash custom/stock kernel of one device to another.

Rom can be installed via official tools provided by manufacturer or by using custom tools. Usually when you flash a STOCK ROM, it flashes SYSTEM+KERNEL+RECOVERY. However, some unofficial tools can help you flash any one component of the ROM. It could be Kernel/ Recovery or System.

RECOVERY

Recovery is also a part of ROM which is basically a backup mechanism of your device which lets you install stock ROM to your device if something has been corrupted in your device software. However, many CUSTOM recoveries are available which are necessary for flashing CUSTOM ROMS, MODS to modify your ROM and also you can backup your ROM(called nandroid backup), partition your sd card amongst many other uses. Recoveries could also be flashed via kernel as they are preinstalled.

BOOTLOADER

is basically a lock in your device which doesn't allow modifications to your phone by the Manufacturer. Unlocking bootloader voids your warranty and stops automatic updates of your STOCK ROM. However, you can easily lock your bootloader again any time or manually install STOCK Updates.

Remember you should usually unlock bootloader before rooting unless you are installing a custom rom which is pre-rooted and allows locked bootloader.

ROOTING

This is basically a powerful exploit to take over your system and kernel of your device. It simply means that some system files which couldn't be modified can be changed now. It is as if you have complete power of your ROM and hardware. There are no restrictions from your manufacturer and thus you can change values , overclock your processor or put your hardware in hibernation to increase battery life, turn on/off your cores , speed or enforce 3D gaming cards to play HD games which you couldnot play before. However, this is a very tricky business so if you mess it up and not sure what you are doing, you can really end up with a bricked phone.

Usually apps are used to change these values or it could be done via SDK tools/ programming. To be sure if you are rooted or not, you can install ROOTCHECKER app from PLAYSTORE.

ADVANTAGES OF ROOTING

- You get full access to your phone's Hardware and software

- You can Overclock CPU clock speed and make phone faster

- You can Install many mods to improve camera, audio and video playback quality

- You can Install Beats Audio Drivers/others to enhance audio output

- You can increase speaker / earphone volume using volume hack

- You can Install Custom ROMs and Apps

- You can take the hell out of your device and Improve user experience

Rooting is safe and reversible, You can unroot your phone if you want. It won't void you're warranty etc

DISADVANTAGES OF ROOTING

-Chance to brick your device if the wrong software gets flashed. This can be EASILY reversible

-Warranty is void. You can flash STOCK ROM again and no one will have a clue you did that. So it can be reversible.

-Because, after Rooting you give permission (apps prompt, it's not by default) to apps to change values so if you give it to a malicious app, it can result in Viruses or security/privacy breach.

In all honestly, I am using rooted devices for over 5 years now and I never had any problem with viruses however, I have bricked my device innumerous times by accident. (I have flashed and rooted my device almost every one to two weeks and I have bricked my devices so many times in testing phase of Roms). I was always able to retrieve back the device with some tools and thus it was not much of a problem.

DIFFERENCE BETWEEN GOOGLE NEXUS DEVICE AND A NON NEXUS DEVICE

GOOGLE NEXUS DEVICES give you vast freedom to install custom roms and it is comparatively very easy to unlock bootloader of these devices so a custom Rom can be flashed. (Flashing rom is equivalent to installing windows in PC). You can understand that a Nexus device only needs one command to unlock its bootloader while others could trouble you a lot for that.

Also, Google is very quick with updates on their devices which mean that you will get the latest software updates officially as they come out. Thus, even staying on STOCK ROM is not a bad choice for many users. Every update increases stability and gets rids of bugs. And of course, sometimes the bugs are not ironed out well and come back

NON NEXUS DEVICES do not give you as much freedom as a Nexus device. It is usually much harder to unlock their bootloader, develop on these devices and usually some exploits are needed to run custom ROM/root/kernels. Manufacturers or these devices try their level best

to narrow down the exploits as in other words, the more exploits a device has, the less secure it tends to be.

SOME CUSTOMISATION DIFFERENCES

As it is a nexus device so Asus has no say on any customisation at all. Thus, Nexus devices are said to run the PURE ANDROID and give you the best android experience in my opinion. However, usually manufacturers customise pure android from Google. To understand better, Google is responsible for development of the android OS so every new version is made by Google and then it is open sourced to manufacturer of different devices. Manufacturers like Samsung/Sony/Motorola/HTC customize the code provided by Google to customize it to their likings. This can result in some added options but can also result in slow performance if there has been too much customization from a device maker. Google itself is only responsible for the software and DOES NOT make any hardware itself.

Also, many manufacturers take a small fee from some app developers and install their apps with every device they produce. It is good news for app developer and manufacturer but usually a burden for users as not only they hog RAM, diskspace, and slow down the device they also are useless to many users. Referred to as BLOATWARE

SUPPOSE YOU HAVE DECIDED TO INSTALL CUSTOM ROM/ KERNEL.

This is a short synopsis of steps which are explained in details later in the post :

1.Unlock your bootloader

Some phones have unlocked bootloaders out of box (Not anymore)

2.Root your phone , which can be done via flashing a custom prerooted kernel or by binary method. There are innumerous ways now actually so usually visiting your device forum will help you find it.

3. Flash a recovery. This step can be done before or after unlocking your bootloader. Even you can root your phone via flashing SuperUser in recovery. However, sometimes, you need a rooted device before you can install a custom recovery using exploit/ scripts method.

SOME COMMON MISTAKES AND PREREQUISITES:

1. Make sure what ever you do, do it as administrator on your PC.

2. Make sure drivers are installed properly for your device.

3. Make sure, USB debugging is ON

4. Unknown Sources is ticked as well

5. Windows 7 is usually quick to install drivers itself. In windows 8 however you have to manually install drivers.

6. There are tools like SDK which is about 500mb which can help you to install drivers/fastboot etc but this is the long route. I suggest you just find platformtools in attachment which would be enough for cmd commands.

UNLOCKING BOOTLOADER :

I will give you a rough idea and it is NOT a guide to unlock your bootloader !

Basically, when you buy your phone it is locked from the manufacturer so no changes can be made to the software(STOCK ROM & KERNEL ) and thus this way, they can stop users to modify their software which might damage the device and they do not want to be responsible for that. So unlocking bootloader voids your warranty. However, this can be reversible.

ROOTING :

What you do in rooting is either flash a kernel via fastboot or exploit your device using binary method. This gives you permenant root, however there are ways to get temporary root too.

ROMS & KERNELS :

You choose a rom to your likings and then flash it via recovery. Usually the instructions are given on every rom as there is slight change as to how to flash it.

There many Roms & Kernels made by developers after lots of hardwork and testing. Thus every rom that surfaces might not be good for you but best for another user. Thus, it is never good to compare roms. What might work for you might not work for another.

I hope this helps!

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