When you purchase mobile on monthly installment. That mobile will be sim carrier locked. And you must imei unlock mobile to use any other sim card. When mobile is carrier locked you can only register on particular gsm or cdma network as per sim card. This is done with imei number. And if you insert other carrier card it will show error that wrong microchip, invalid microchip or enter sim restriction code.
When smartphone is sim network locked, it is done with imei number. By modifying this number you can carrier unlock any mobile. To change this number you must rewrite efs partition of cellphone. But this is not as easy as you think. There are many software available for this. But it needs root permission, also require usb driver as per mobile model like lg, Samsung, Nokia, Motorola huawei. And applied imei number must be valid as per country. Or number must be genuine as per location. After that you can register on any gsm cdma network as mobile imei number is changed.
Here I am providing engineering mode method for this process. This can also repair imei related error and network registration problem.
1) First install rooting software on computer. There are many rooting software, depending upon mobile model different software will work. Try one or two different software. Softwares are available on trial version also.
2) Enable usb debugging on mobile. For that go to setting – about device – tap 7 time build number then you can see develop option menu – within it there is enable usb debugging select it.
3) Install usb driver for mobile phone. Usb driver are available on official mobile site. Even you can search internet for that.
4) Now enter into engineering mode using following command.
*#*#3646633#*#* and there is another code *#446633#. These smartphone secret code for engineering mode. This will work on most of the mobile and work with almost all android operating system.
5) Once you are in engineering mode look for folder cds information folder. This folder has information about imei number. When you get invalid imei error, then rewrite this folder will fix problem. I also suggest to take backup of mobile before doing this. Make sure you have back up of all imei related information. So if anything goes wrong you can change it to default. And mobile will work fine.
6) There is cds folder within root folder. Here search for modem / radio information. In mobile normally radio is consider as modem of mobile.
7) all modem related information is gathered inside radio information folder. And if you have two sim card slot then you will find phone 1 for master sim slot and photo 2 for slave sim slot. For mobile carrier network unlock, modify imei number of phone 1. There is specific command for imei modifying. Go to command prompt of phone one where you can see cell with at+ type below sim one imei number change command.
EGMR=1,7, “Valid imei number as per location. Each mobile company has specific way to provide imei number as per country”. After that tap on send. You must reboot mobile to apply this changes. Now to change second number again goes to radio information and tap on phone2. Use this command At command prompt shell start with at+=1,10 “dual sim slot valid imei number “. This will rewrite second sim imei number.
Now insert any other sim card to mobile. For example if smartphone is at&t, Verizon locked then insert sprint, roger, Vodafone carrier card it will work. That means mobile is sim unlocked.
Importance of imei number.
Imei is very important identity of cellphone. It is used for mobile tracking. When owner lost mobile, police ask for imei number for registering complaint. IMEI stand for international mobile equipment identity. Without imei number, it is very difficult to track mobile phone. Even when sim card inserted to mobile. And mobile try to register on gsm or cdma network. It verifies mobile number from imei details. Only imei number allows smartphone to register on particular carrier network.
Imei number is equally important for sim network unlock code generation. Without this detail, no software is able to generate sim carrier unlock code for LG, Samsung, Huawei, htc and Motorola. It also requires location where sim is network locked and some other detail related to mobile number. Customer care also ask for mobile number which is about to unlock.
Imei is also linked with warranty details. So when someone visit customer desk, support executive ask for imei number. Most of the mobile company making record of these details. This number also provides details about mobile model.
How to find imei number of smartphone.
To find imei details of any android smartpohone. Start android mobile enter into setting – within it find general menu – here look for imei option. There are two different imei numbers if mobile is having two sim slots. First imei number is used for sim carrier unlock code generation. *#06# this is most command and working code on almost all mobile. On mobile bill this number is written. Also on battery sticker imei number is generally noted. Many apps available on play store which can provide mobile hardware related information including imei number. Those apps also provide software related information. Most of the apps are free to use.