[General Questions and Answers] basithn95:
How to Fixing Lenovo S850 no Service Issued, 100% Work - Got this posting from the comments one of blog reader, a lot people got this problems when modified Lenovo S850. Beside Lenovo S850 when you got invalid IMEI and no service issued on your device, you can fix it by restore the IMEI and it will fix the problems other then Lenovo S850.

I don't know this guide can be use for other china device or just Lenovo S850 so if you try to another please give some word on comment.

No service is cause by NV file corrupt, so using flash tool we gone read back NV file and the flash it back to our device, if you do right this procedure than it will revive your device from dead. Please read careful step by step because it think it will complicated.

Disclaimer : This guide for educational purpose only, We not responsible if your device bricked after following this tutorial. (DWYOR)

Download

•	SP Flash Tool v3.1320 ↦ for this guide actually you only need the flash tool, you can use any version of flash tool but recommended to use v3 flash tool.

•	S850_ROW_S215_150114 ↦ 1.1 Gb, because this guide is for Lenovo S850 then you need to download Lenovo S850 stock ROM, for another china device then you need to search it on the need.

•	NV_RAM ↦ Lenovo S850 NVRAM block, cannot be use for another device.

How to Fixing Lenovo S850 no Service Issued, 100% Work

1.	Download all files and place on the same folder, so you can easy to search the needed files. Extract the both files too and then go to flash tool extracted folder, run flash_tool.exe for windows 7 or later please use administrator privilege

2.	After you can see the flash tool windows, now pressALT + CTRL + V. This will make flash tool run onAdvanced Mode, you can see on the flash tool windows bar. On the Download tab click Scatter-Loading button and the navigate to ROM extracted then select MT6582_Android_scatter.txt this will load all ROM files to flash tool.

3.	Click Windows ↦ Write Memory this will add a tab, then select the Write Memory tab, like on the below picture

4.	Open scatter file that you find on the extracted ROM, using word pad or notepad. Search for NV word, you will see three address on the scatter filelinear_start_addr, physical_start_addr andpartition_size. Put the linear_start_add on the Begin Address (Hex) and partition_size on the Container Length (Hex)

5.	Click on Open RAW Data, select the NV_RAM file that already downloaded

6.	Last click Write Memory button, turn off your device because Lenovo S850 using non removable battery you must make sure that your device is completely turn off, connect your device to flash tool using USB cable and flash tool will recognize your device and begin to start flashing process, wait until you can see GREEN CIRCLE in the middle of flash tool.

7.	Done, disconnect then try to turn on your device and normal boot. See if the service already on and can be use on your device.

Done, Congratulations i hope your Lenovo S850 already fix and can be use to make call and receive messages again. Please leave comments if you found any problem or broken link regarding this guide

Credit: GSM Somanadhan (smartphon2016 blogspot in)