Is it safe to delete nvram folder? I've got a Mediatek based phone (Meizu 7 pro plus) and I've lost the IMEI2 number. I mean that it is null into phone settings, but filled when I do *#06#.

I've tried many things, such as:


A Factory Reset and wipe out data.
Install an older official ROM (and wipe out data).


But each time:


When I use the phone for the first time (just after wiping it out, or flashing), the IMEI2 is filled and I can call, SMS, etc. as long as I don't restart the phone.
If I restart the phone (no matter how many times or the SIM slot I'm using), the IMEI2 is null and I can no longer use the mobile network.


I've tried to use softwares claiming to change IMEI numbers, but they doen't work.

I've tried to set it with the engineering mode (send AT+ command), but it refuses saying that the operation is not allowed on a "userbuild" (and yes, I've tried to insert spaces at many places between or after some symbols). 

I've seen people recommending to delete the whole nvram folder (on many sources and people replying back that it worked for them). But I don't know what is the purpose of that folder (I do know what is a non volatile RAM, but I have no clue of the impact of deleting it on Android).
After a backup, I tried to delete the nvram folder (via adb root ; adb shell ; su - ; mv /data/nvram somethingelse). I do confirm that this folder is created from scratch when you reboot the device.

So the answer is yes, it is safe to delete the folder.