[ZTE Maven 3  Questions & Answers] amart79196:
This sounds like the IMEI is blanked out. I bet it got corrupted. I'll explain below.

The only firmware are the ones in this thread that have the boot.img file modded as far as I know. Would be nice to see an AOSP version for this phone once we all can easily root and not kill the imei.

Can we assume that you are referring to the one's listed in this thread? Maybe we should collectively start a NEW thread once we have some success with the step-by-step VERIFIED way to actually gain root.

Is Windows 10 that you are running 64 bit or 32 bit?

Please post a link so that we can all download and be on this version.

I think yours as well got the imei corrupted by attempting this.

So, I have a UAT FRP 9.0.1 Tool and also just purchased the UAT MAIN tool version 19.0.1. (currently waiting for them to get the 19.0.1 working). The Main 19.0.1 which is different than the FRP version has very similar functions, but the FRP is limited for the ZTE. The Main has its own tab for the ZTE and has many more functions including Security wipe and restore. I believe those functions are what is needed for the repair of the IMEI which is causing the network locked feeling that both of you are experiencing as well as I. I can say this, my phone used to show 4gLTE and mobile signal BEFORE playing with trying to flash the boot.img file. Im not sure what actually changed it so it now just looks like a triangle with no signal reading.

Is this what you both are experiencing when you say that the phone is network locked?

The reason why I am saying that the IMEI is corrupted is that when I have the phone connected in mode, regular, ADB or EDL, when using the UAT FRP 9.0.1 tool I am able to see that the IMEI1 is showing a blank. Also, the carrier info is not showing anything either. I have a feeling that this is where the issue is. There are instructions in using the UAT tool to actually fix this, but the UAT FRP 9.0.1 does not do this for the ZTE. Only the Main version seems to be able to do this from what I have read, although I have not personally tested this theory.

Two other points to make quickly:

1. XDA user George_jetson who posted here in this thread that he got root, who was the first to say that he actually got root, also said that he used the UAT. Although I find holes in almost anyone who has claimed root, Im I can't say for certain that their are or aren't being 100% truthful. At least I will be able to tell one way or another if UAT actually works and there is no 1 second trickery in starting one program and opening up another one to try to get it to flash and then finding yourself with a no mobile network phone. I did message him and his account is suspended, not sure of the reason why.

2. When I actually get the UAT Main Tool working, and I find success hopefully, I will post the files that the TWRP guy mentioned to post up so that they can start working on getting a custom recovery for this phone. In actuality, is UAT can actually do it without the F*ckery of opening up programs, closing quickly and jumping through hoops and not killing the network (again, i'll still bet that is a corrupted IMEI unless someone smarter can weight in on this and enlighten me as I am no genius), then maybe someone much smarter can find out how the UAT is actually doing this and make is a free software loader or maybe even FIX the available ones out there to not kill the network and that doesn't require f*ckery.

I'll post back once I get the UAT working which I hope to have this done soon since I bought it roughly 24 hours ago, although it is now sunday and they might not be around on sunday to do the activation.