What is this ROM?
R-O-M refers to the Read Only memory. ROM is an operating system that runs the droid and is stored in the phone's read-only memory.
Classification of two types of ROM: [ROM]:
Stock ROM is pre-loaded by the manufacturer and is optimized for device configuration. There are many limitations for the user
Android is open source so developers can accept code, customize their taste, new operating system. A custom Android operating system, usually stored on the read-only memory of the mobile phone and replacing the manufacturer's operating system.
BEFORE INSTALLING A PREVIOUS ROM:
Before installing a custom ROM, a device must be rooted. The roots of Android devices mean the unlocking of the manufacturer's restrictions. Rooting allows you to customize the number of customizations to your device. Recording from guest to super user changes permissions. This is a protection measure, but some do not like them because it restricts them from customizing them. But do not forget that roots of the device invalidate the warranty, but some unique ROMs are worth it.
The installation of a custom ROM has both advantages and disadvantages:
BENEFITS FOR INSTALLING A CITY ROM:  LOWEST ANDROID VERSION:
One of the most common reasons for installing the updated android version. Users can install the latest version of Android on their phone, which will allow the appearance of old phones. This not only gives a new look but gives the user a better performance as the newer version is more stable than the old one.
Another reason people choose to install on the Android phone are a lot of customization. The sexy and fascinating themes add a new look to their device.
OVERCLOCKING AND UNDERCLOCKING:
This is not really beneficial for installing a custom ROM, rather than the kernel that is the user interface (a system kit like the operating system). Otherwise, it allows the user to override or reduce their device. Overclock means running the processor's CPU or GPU at a higher speed than the one designed by the manufacturer. This gives you more performance, but I do not recommend it because it may damage the device. Underscoring is the opposite. This system modification works at a lower speed than the intended one. This ensures longer battery life, but in return for some performance.
During rooting, users can remove applets installed by the manufacturer, but the user must choose which application they want and which they do not and manually remove each, which you do not want to use. Although unique ROM developers remove these applications while creating these ROMs, they do not include them in their operating system, so users only need to install and now your device can be pinched. :
Custom Modules available for custom ROMs will attract users to install on the device. These custom modes can be very simple, such as increasing the manufacturer's limit beyond the size of a custom ROM, such as multi-window mod or pie controllers mod. ] This allows the user to experience a wide user interface and choose the most appropriate one. Like the Sense user interface for HTC phones that are connected to many different phones, enabling users to get HTC phones without buying HTC phones. The user can also choose to install the android on the phone that is faster than personalized, such as Samsung or HTC. :
Another reason for the user to hesitate on a device that installs a unique ROM is the brick factory fear that makes the device unusable and is nothing more than a brick block. They mostly fear that you can not recover a device from that state.
BATTERY LIVE PROBLEM:
These ROMs can not be fully optimized on the device, which results in battery life that does not leak more, do not charge properly or even damage the battery.
These ROMs may not support the device of any hardware that does not work with unreliable hardware or other things, such as the camera, or worse.
These ROMs have not been tested as pre-loaded by the manufacturer, so they cause errors that produce instability, such as violent closure of applications (which may be annoying) or a random restart on the phone or phone that is stuck in a bootloop (really frightening reboot).
CONCLUSION:  Here are the advantages and disadvantages of custom R installing OM, but you do not fully know what is going on while you try it. I use a custom ROM on my phone, and I'm happy with it. But everyone has their own decisions, so you can do it and keep in mind that neither I nor the ROM developer are responsible for what is happening to your device. ——————– HAPPY LIGHTING —————————- —–