Follow the steps -:
1) First, you need to have a rooted android 4g handset.
2) Then Install Xposed Installer app.
Now Download IMEI Changer App in your mobile.
3) Now go to Xposed Installer & Activate Framework then go to Modules Tick on IMEI Changer Pro app.
4) Now open the IMEI Changer App in your mobile and enter the IMEI Number of your LYF mobile in the app and click on Apply button.
5) LYF Flame 2 IMEI Series 911501450159XXX replace with XXX any 3 digit Random Number.
6) Now Switch Off your mobile phone and insert your Jio Sim Card in Slot 1. And restart your mobile phone.
7) Now your jio sim card will be activated in another device and if you don’t get the signal in this device then go to Settings > More > Mobile Networks > Network Operators > Search Manually > Choose Reliance Jio.
8) After that again go to Settings > More > Mobile Networks > Access Point Names > Create New APN
Name: Gogotricks
APN: Jionet
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9) Now Go to Dialer and Type *#*#4636#*#* and Now Select LTE Only Option.
10) Now Open Play Store and Download JioJoin App and Configure With your Jio 4G sim.