You buy a new smartphone and go joyful until a new custom rolled up again. It works smartly, and toys go better, faster than stock, but then OTA arrived, a new kernel came out, and Magisk has already been updated - it's time to install updates and get bootloops. Yes, of the total number of Android smartphone users, the share of those who use custom apps is extremely small. However, people still come up with strange thoughts like: “I wouldn’t flash my Xiaomi so that it would fly like a rocket.” On this occasion, an article that talks about custom Android firmware from A to Z.

Custom firmware and their classification

What is custom Android firmware? This is a system that third-party developers are involved in, that is, any unofficial firmware. In most cases, the distinguishing features of such firmware are a different shell, a modified system core, wide customization and many different goodies that are not in the official Android firmware created by the manufacturer. Most often, such firmware works faster than official ones, but less often they work more stable. There are a huge number of custom, which are divided into types, the study of which we will now study.

Here are the basic variations of Android firmware:

1. Official from the manufacturer (stock)

2. Custom built from source

3. GSI Firmware

4. Ported firmware

And now about each in more detail. The official firmware from the manufacturer is installed in the smartphone from the factory: that is, you buy the phone with it. It was made by the department of the manufacturing company, which is responsible for the software of its devices. Also, any self-respecting company provides the source code for the firmware they created, the same source codes. Next on the list is custom firmware compiled from source code - the one that was collected by third-party developers. Such firmware is modified and may include all sorts of improvements and customizations that were not in the official one. Our next GSI firmware differs from the two previous ones in that when it is installed, the Vendor section is not affected, since the GSI image is the system image. These GSI firmwares work much slower and less stable than those compiled from source codes. Well, the last one is the firmware port from another device. This is a firmware that is completely transferred from another device and modified to work on a specific smartphone. For the most part, these are the most buggy firmware, since the system is not only not native, it is also torn off from another device. But they are used: for example, the same lovers of branded shells of various devices. There is a huge amount of ported firmware from OnePlus smartphones with their OxygenOS shell, which many people like. for example, the same lovers of branded shells of various devices. There is a huge amount of ported firmware from OnePlus smartphones with their OxygenOS shell, which many people like. for example, the same lovers of branded shells of various devices. There is a huge amount of ported firmware from OnePlus smartphones with their OxygenOS shell, which many people like.

We will consider exactly those custom that are assembled from the source code. There are a number of reasons for this, namely: such firmware works faster than others, they are more stable and are a full-fledged replacement for the stock one, as they were assembled for a specific device, and do not have only a System image like GSI and are not ported. Naturally, not without taking into account the build quality. At the moment, custom is widely used among many models of various brands, also, the community of custom creators is constantly growing and developing, so finding a stable firmware for your smartphone is not particularly difficult.

There is a classification of firmware, showing on the basis of which source code the base for the assembly is taken:

1. AOSP - Android Open Source Project. It is a completely bare Android system, on which shells are subsequently “hung”, like One UI, MIUI, OxygenOS and so on. Even Google Pixel smartphones are not AOSP, they have their own shell.

2. CAF - Code Aurora Forum. A Linux Foundation project that contains code for flashing smartphones based on Qualcomm processors. Firmware based on CAF tags may not be the most stable, but due to the latest driver versions, they have a number of advantages: better performance, faster internet connection, good autonomy and improved sound quality.

3. LineageOS is a custom on which many other customizations are based, like CRdroid, Resurrection Remix and the like. Initially, there was CyanogenMod: it was he who was heard, and was constantly developing. Later renamed to LineageOS. At some point, so many changes were made to AOSP by the developers of the line that they began to use it as a base for other firmware.

Why do we need custom firmware?

To the simple user - there is no need. If you want to mock the device, or vice versa, transform it with the help of a newly minted custom on the latest version of Android and turn everything in it to make it the way you want, this is yours. When a person puts it in custom, he takes full responsibility for the device’s performance, and in case something goes wrong and you can’t fix your smartphone, then this will be your own business. Most likely, your case will not fall under the warranty, even if the hardware of the smartphone is broken. You will have to at least force the SC to carry out normal diagnostics in order to exclude the most stupid cause of the breakdown: custom. Also, almost any software failure during firmware can be fixed at home without resorting to the help of service center employees. So if anyone decides to sew, know: a brick is not so scary. In any case, there are a huge number of "how and what in case" guides on the Internet.

Considering the use on a daily basis of custom firmware created by a good builder, one can experience a high smoothness and speed of the user interface compared to stock firmware. An increase in performance in games and an increase in autonomy are also provided. It is quite possible to improve the quality of sound, photo and video shooting of a smartphone. If not from the main, then custom often has the latest security patches and system updates that increase the stability and speed of the device. Also, depending on the firmware, there are customization options that were not in stock.

Firmware installation process and drive partitions

So, here we come to the most important thing: installation. This is a universal instruction for all smartphones, which will work when installing most of the firmware. But, on some devices there may be installation features that need to be specified in the source where you get the firmware from. Paying attention to the nuances is really very important, because if you sew "as you want", then at best you can get a "bootlap", and at worst it will be a "brick". All manipulations must be performed on an already unlocked bootloader . Unlocking is carried out using software from the smartphone manufacturer, or by Fastboot commands. For details - in the subject of your device.

In preparation, we download everything that is needed to install the firmware: the necessary TWRP, the latest Firmware (if available on your smartphone), the firmware itself, a custom kernel (suddenly needed), patches and fixes (if necessary), optionally GAPPS (Google Apps), decryptor (removing Data encryption) and Magisk (Root-rights). After everything has downloaded, the best option would be to transfer all these files to a USB flash drive in order to boot from it. Of all the above, to install the firmware, you only need TWRP and the firmware itself, but, most often, people sew everything else, so here is a sequence that includes the most common firmware installation.

• We put TWRP on your smartphone:

TWRP is a modified version of Recovery (recovery mode), in which we will perform all the manipulations. To do this, just install the drivers for your device on your computer and flash the image of the desired TWRP to the "Recovery" section (if not booted, then to Boot) through a special utility depending on the smartphone processor platform: MediaTek or Qualcomm (SPFlashTool or Minimal ADB and Fastboot ). Choose TWRP for taste and color, the main thing is that it works. If TWRP is already installed, we immediately start from the second point.

• Clearing smartphone partitions:

The main sections of the smartphone that are visible in TWRP:

1. Dalvik/ART Cache - Dalvik/ART virtual machine cache.

2. Cache - system cache.

3. Data - a section with the data of the system and all programs installed in it.

4. System - the system itself. The same GSI images are installed in this section.

5. Vendor - binaries, configs, libraries. In general, everything that the manufacturer stuffed into a smartphone for its normal operation.

6. Internal memory - you have it on the main page in the explorer. Files created or downloaded by you.

7. Micro SDCard - mount point for a memory card (flash memory).

8. USB OTG - mount point for a flash drive or hard drive connected via an OTG cable.

We go into TWRP with the key combination of the smartphone that enters the Recovery mode and clean up the smartphone so that it can be customized to a clean drive. To do this, in TWRP we are looking for an item related to cleaning and go into it. There we also observe sections of the smartphone and checkmarks next to them. We need to check the boxes next to the sections Dalvik / ART Cache, Cache, Data, System, Vendor (optional), Internal memory, but do not check the Micro SDCard and USB OTG, which indicate an SD card or an OTG drive, depending on where you have the files for the firmware. After that, we just swipe to clear partitions (you will lose all data on your smartphone). Next, we need to format the DATA partition. This is done in the same place in the cleaning menu with the introduction of confirmation in the form of the word "yes". After successfully formatting the DATA partition, we need to restart in TWRP. What for? This may be necessary to correctly determine the partitions by TWRP itself in order to avoid errors when installing the firmware. Also, there is an OTA update option: installing the firmware as an update to an existing one, without formatting the memory.

• We boot back into TWRP and proceed with the installation:

  We select the drive on which the necessary files are located and put everything in the following sequence:

  1. Firmware

  2. Firmware (The system we install)

  3. Reboot in TWRP (For the reason described above)

  4. Core

  5. Reboot in TWRP

  6. Necessary patches / fixes

  7. GAPPS (Google Services)

  8. DFE (Disable Encryption)

  9. Magisk (Root rights)

• Reboot into the system and further configure it to your taste.

There may be fewer components in the installation sequence. As I said, it’s enough to install only the firmware in TWRP and if it doesn’t need anything else, then it will start and work.

Problems installing firmware

Errors may be different, but are solved by the same algorithm. If TWRP gives an error, then:

1. Check what firmware you are installing. Anything can happen, you can not download your own by accident.

2. Re-read the instructions if there is one, suddenly missed something.

3. Download the installation zip with the firmware (it may be broken).

4. If 1-2-3 did not work, then we clean up the partitions and format the Data.

5. Extreme case: flashing with stock firmware through a proprietary flash driver.

6. Only if you have a programmer and the ability to work with it: we sew a drain through it (it can solve the problem if the usual flasher did not help)

7. We are trying to restore the smartphone according to the individual for each instruction "Recovery from a brick", which is searched for in the theme of your device.

8. If not at all, most likely the problem is in the gland. Therefore, the only option left is the service center.

All problems that may arise in the working system are solved by installing the "Fix from Vasyan", changing the kernel, or installing another custom.
If you have already decided to do this, then look for and try to fix it, or even better show the others how you solved your problem if there was no solution before you.

Conclusions: do we need it or not

To begin with, you will have to suffer a little, and there you will already gain experience and it will be possible to sew without guides and fix any problem yourself. Getting pleasure from using your smartphone will not be such a rare occurrence. Looking for something special and better than stock? Ready to make time for it? Forums with firmware are waiting for you. "Custom will always be better than any stock" - this phrase will only make sense if the firmware is well assembled, has a kernel with various optimizations and is cleaned from junk applications. It's not about taste anymore, it's about how it really is.