sigmakey cannot ZTE Z970 New security FW

* daemon started successfully *
^ ROMaster Composite ADB Interface
Version: Linux version 3.4.0-g1af7f82 (xueyibing@scm12) (gcc version 4.7 (GCC) ) #1 SMP PREEMPT Fri Jul 31 12:22:25 CST 2015
Phone model: zte Z970
Android 4.4.4; Firmware: KTU84P; Date: Fri Jul 31 12:03:24 CST 2015
Version: Z970_MetroPCSV1.0.0B12
Baseband Firmware: .3.0.c9.6-00019-M8926DAAAANAZM-1
Baseband Processor: Qualcomm MSM8926
Date: Jul 31 2015 11:56:18, Jun 30 2015 03:00:00, DAAAANAZ
Software IMEI: 865891028693303
Reading data….Error 00000000:DEAD
why sigmakey cannot unlock this model z970 metro pcs this firmware have a big security how i can patched this fw or i can find another Fw