The principle of ROM brush machine and the technology of ROM fabrication

recently in the study of the knowledge of the brush machine, after watching some tutorials on the net, the understanding of the brush machine or just stay in so mechanical steps, always feel so superficial understanding really bad! So small series to find the following this article, their own study under, really good (well, small is a novice, I hope that Daniel with small series X with small series of flying ... ) and share it to everyone.

This period of time to brush a bunch of ROM, the Android series, CM, Hero, Oldmos, mobile phone camera also brush no longer start (do not know what reason, cups). There is a saying: "Long illness into good doctor", think we toss the brush machine, also have to summarize not, younger brother, far from "good doctor", but still want to put some of their knowledge and experience to write, with a view to the ...

First, the principle of brush machine

Remember the first time you brush the machine, that psychological tension ah. What are you nervous about? Just because do not understand the principle Ah, only see a bunch of tutorials to follow the gourd painting scoop, for fear that the wrong step will be a mobile phone brick. In other words, the brush machine is two ways:

One is the recovery method, that is, we usually put Update.zip into the SD card, and then Alt-s method, this method is called recovery method will be a variety of IMG or file replication operations.

The second is FastBoot method, this method is actually a cool method, white point, FastBoot is the existing partition image file (img file, similar to the image we do to the disc) directly overwrite the write to the designated partition, a bit of violence, It's a bit like the ghost restore of our usual operating system.

Which of these two methods is better, which is not good or low, in general:

Recovery method is more simple, only need to fool the Update.zip into the SD card to the directory, and then into the recovery mode alt-s can be, but with any fool-like things, his flexibility is very small, and error also do not know how to solve. Generally do ROM master in order to ensure the reliability of the ROM, in the installation process will be some of the installation environment to make some determination, and your mobile environment is ever-changing, ROM master is also very difficult to consider comprehensive, in addition, recovery program itself has some environmental validation.

FastBoot method is more flexible, more powerful, fastboot method does not need to rely on recovery, and even the Linux bottom brush bad recovery mode can not enter the situation also through FastBoot Fang brush back. FastBoot mode is actually called SPL to brush the machine, so if the brush SPL is bad, the fastboot mode should also not enter, that is, brick. FastBoot method requires you have FastBoot program on the computer, while the phone to enter FastBoot mode can operate, about this knowledge, please see Google * ^_^ *

Second, back to the Android system in the various partitions (may be partitioned this statement is not very accurate)

I learned that the partitions in the Android system are:

Hboot (We brush the SPL is this thing), this partition is the most basic boot partition (similar to the BIOS in the computer), this area is broken, almost become brick, so we have to brush SPL so careful ah.

Boot, this partition should be the boot partition of the Linux operating system.

Radio, this partition is the mobile phone of some low-level device related driver or function program bar, such as telephone and texting, different system version will have different radio matching, we usually brush the high version of ROM, if not brush the high version of the radio may cause the call is not normal and so on.

Recovery, this partition is installed is the aforementioned recovery program, this brush different recovery version can bring different functions, interested students can be based on the source of recovery to compile their own recovery out. In general, however, the most important thing to brush recovery is the root authority.

System, is the main function of the general release ROM partition of the program, we say that the ROM function and the custom-built program should be based on the modification and compilation of this partition.

UserData, user data, don't say anymore.

cache, cache, usually used for OTA upgrade when the buffer, we say that the brush SPL can increase the size of the program area is mainly to shrink the size of the area and then increase the size of the program area partition.

Analysis of a city typical ROM

We usually upgrade the ROM is packaged into a suitable recovery way to brush the machine package. Packages that can be identified and processed by the recovery program should have a fixed format, and some of the important constraints I understand are as follows:

1) must be a standard zip compression package;

2) Recovery script must be deposited in meta-inf\com\google\android\update-script;

3) Some other certificates and signature information should be placed under \meta-inf\.

Iv. are there any possibilities for us to customize our own ROM?

Theoretically, we can customize it ourselves.

The simplest customization should be to take an existing thought is still good base ROM, replace some resources, add some system to bring the program, and then pack the release; then play advanced, you should modify some of the system's own programs, such as the Chinese some system original program; play a bit more advanced, You should go to the Android official site to download the Android system source code to compile, and based on the system-level customization and porting.

If it is a simple bit of homemade ROM, the main should be to solve the following problems:

1) Select a good and stable kernel and base, that is, which boot.img in the Update.zip package, in addition, most of the system directory is directly available, it can be used as a basis for custom ROM.

2) Modify the system. For example, you can customize things like this: System\etc\apns-conf.xml, which is the APN access point, system\etc\hosts, this is the setting of the host file, now there are a lot of people with the package can not bind Gmail, You can add one to this host file: 74.125.93.113 android.clients.google.com (Of course, how long this address can not be said) ... There is something else to customize on their own to look over to see see.

3) The re-packaging signature of the ROM. The previous article has introduced a ROM package of the basic structure, but completely according to the structure of packaging or can not be recovery installed, because there is no signature! Rom signature can download an automatic signature tool auto-sign, specifically to where, please google. (Note: ROM signature tool requires Java1.6 support, so the system has to have JRE1.6 environment).

Further down is a bit advanced, at present only to pay attention to these basic things, mistakes are unavoidable, welcome to correct, Pat brick light.

                                                     & nbsp;                          & nbsp;                          & nbsp;                          & nbsp;                          & nbsp;       original   Happylo

from http://www.morecomtech.com/community/article/sjjc/w2015090005.php

I'm sharing the angel divider line ********************************

In addition, share an article on the common sense of the brush machine:

Brush Machine Overview: http://www.morecomtech.com/community/article/sjjc/w2015090001.php

The principle of ROM brush machine and the technology of ROM fabrication