my signal is not connected

[Vebry kris nanda]

when I lowered the version of android pie to oreo and my image was null and my signal was illegible, after that I searched for a way to restore my imei first and I edited my image via the qpst application and it made my imei back but my signal was still not connected , and when I release or add to my sim card it makes my cellphone bootlop but when I insert the card in sim 2 it returns to normal but the signal is connected

Please help me
sorry my english is very bad

 

[correconejito]

when I lowered the version of android pie to oreo and my image was null and my signal was illegible, after that I searched for a way to restore my imei first and I edited my image via the qpst application and it made my imei back but my signal was still not connected , and when I release or add to my sim card it makes my cellphone bootlop but when I insert the card in sim 2 it returns to normal but the signal is connected

Please help me
sorry my english is very bad

This tutorial might help you https://forum.xda-developers.com/mi-a1/how-to/tutorial-downgrade-9-0-to-8-1-edl-imei-t3879624
I
Before doing anything create a back up with QPST of your imei information because you will lose it again after following the tutorial. Also its good idea to back up boot and efs in twrp