For those who are yet to root their Gionee Elife S Plus running on Android 6.0 (Marshmallow), Team Hovatek has created an easy guide @ https://blog.hovatek.com/how-to-root-the...rshmallow/ .
We've however been receiving complaints from users ending up with Invalid / Null IMEI after upgrading from Android 5 (Lollipop) to Android 6 (Marshmallow) and rooting. This brief guide will teach you how to resolve this.
* Download the Lollipop firmware @ https://forum.hovatek.com/thread-389.html
* Flash it to the phone using SP Flash tool @ https://forum.hovatek.com/thread-159.html
* Write back your IMEI to the phone using any of the methods @ https://forum.hovatek.com/thread-116.html (MTK Engineering is easiest)
* Do not factory reset the phone from this point
* Upgrade to Marshmallow by installing the OTA update
* Flash TWRP recovery as instructed @ https://blog.hovatek.com/how-to-root-the...rshmallow/ but do not root the phone yet
* While still in TWRP, backup Secro and NVRAM
* You can then root by flashing SuperSU as instructed in the rooting guide
* If you have Null IMEI after rebooting then simply boot into TWRP recovery and restore your Secro and NVRAM backup