[TUTORIAL] Android unable to Make Call and SMS caused by Invlaid IMEI/ NVRAM Error

[TUTORIAL] Android Unable To Make Call caused by Invalid IMEI/ Wi-fi NVRAM Error 0x10

If you see the following error at your Android Smartphone "NVRAM Error 0x10" or Unable to make a call or receive/send SMS, congratulation you have successfully turning your Android phone into Ipod or "Androidpod". Don't worry you have came to right place.

Depending on how serious is the problem, you may need to apply different step of action.

Symptom :  
In my real case, the phone can connect wi-fi and function as per normal, application (whatsapp, internet, etc) are working as per normal, except the phone can not make call and can't send/receive SMS. 

This tutorial is made base on my own experience of S860, 1GB version. The original phone came with China ROM, it was then flashed with International (ROW) version of Kitkat 4.4.2

Do it at your own risk.

Prerequisite:

1. Install USB VCOM Driver   tutorial here
2. Phone must be rooted
3. MTK Droid Tools_253     here
4. * IMEI1 and IMEI2 (in case of Dual SIM) and / or 
5. NVRAM backup file, 
• if you don't have it, pls ask someone using same models of phone to backup his/her and send you a copy of that NVRAM backup file.

NOTE on *IMEI:
You should enter the IMEI obtained from the box of your phone or information under the battery cover. In some cases, a dual SIM phone will have the same IMEI for both SIM slots. In the case that your carrier doesn’t allow this, or if you have other reason you need to change the stock IMEI, you may need to generate/calculate/find a new IMEI with the correct checksum / check digit on your MTK6589 MTK6589T MTK6592 MTK6595 MTK6572 MTK6582 MTK6577 MTK6516 phones

Instruction

Step 1: 
How To Fix/Repair/Generate the Phone Error with Invalid IMEI 

Skip this if you know your original IMEI1 and IMEI2 number, 

In case you do not know what is your original IMEI number, you can generate the IMEI number with several method.

Step 2:
Option 1:
Try the easiest way (no PC required),  (not yet tested by me ):
> Download Mobileuncle MTK Tools
> Engineer mode keypad, *#*#3646633#*#*)
> Connectivity tab
> CDS information
> Radio Information
> Phone 1: at+ egmr = 1,7, "IMEI1"
> Phone 2: at+ egmr = 1,10, "IMEI2"
> DONE

Option 2:
In Case you know your original IMEI1 and IMEI2 number 
(normally it can be found at phone box label or behind battery cover)

1. Rooted Phone, if not pls google how to root your phone
2. Install USB VCOM Driver on your PC to ensure that your PC can detect the phone, skip this if your PC already has it.
3. Extract the downloaded file and run MTKdroidTools.exe  as Administrator.
4. Switch On the phone and make sure USB Debugging is ON (enable),
1. Go to "Setting" >> "About Phone" >>  "Version Information" >> "Build Number" (press 7 times) to enter Developer Mode Activated 
2. Go to "Setting" >> "Developer Options" >> tick (enable)
5. Connect the phone to PC via USB cable data.
6. MTK Droid Tools should detect the phone, 
1. then click "Root" button
2. Look at the phone, the SuperSU or Superuser should prompt you for Root Access permission, click OK or Allow, yellow box at bottom left the colour change from yellow to Green.
3. Click IMEI/NVRAM
• 
4. Look for IMEI 1 and IMEI2 and input the value which you obtain from back of your phone battery cover, or the original boxes of the phone.

• 
  
5. Reboot
7. You can restart the phone
8. DONE

If the above method does not work, you may also try the following (some netter reporting this method also works, but I did not get the chance to try it myself)

Option 3:  (not yet tested by me )
Downgrade and the use MTK Droid Tools

1. If your phone is already upgraded to Kitkat 4.4.x, then you may try to downgrade to JB 4.2.x
2. Root the phone using Framaroot
3. Install Root Explorer, then delete the whole Folder of /nvram
4. Change IMEI using MTK Droid Tools (follow step 2 option 2,above)
5. DONE !

Option 4:  (not yet tested by me )

Some user feedback that changing IMEI using MTK droid tools many times,but does not works. also tried Maui meta, and error appear "Execution Warning: NVRAM database file is incosistent with target load"

This's ONLY Warning but no error ! MTK IMEI lid is almost standart and this fact use any tools that fix IMEI in META mode. Try further with this 

1. BPLGUI ====>"IMEI download" ===> "Upload from flash" if read IMEI OK(see Notification Area on the botttom :"Read NVRAM successfully") 
2. fix it and press "Save to flash" Good luck!