Error loading sparsechunk.7

Hello everyone,

First of all, my name's Rafael, and I own a XT1225 Moto Maxx BR.
I've got a problem with it.
After trying to reset it to factory settings, it got into bootloader infinite loop.
I'm not able to enter in the system, to enable oem unlock, so it is currently locked.

The thing is I'm trying to repair it by flashing the stock rom Brazil retail 5.0.2, I'm able to flash almost all of it, except the one called system.img_sparsechunk.7, I get "invalid signed image" error.

Is there a way to solve this problem? Or I'll end with a brick in my hands?

I don´t know if you guys can help me, or what other informations you might need to help me.
So if you need anything please ask, and I'll be happy to get it for you.

Thanks for you help!