[Moto G Q&A, Help & Troubleshooting] a_gert:
Alright, let's see what we can do for you! First things first, download the XT1028 4.4.4 stock ROM from here:

http://www.filefactory.com/file/5cg..._4.4.4_KXB21.14-L1.41_42_release-keys.xml.zip

It's big, filefactory is slow, and that's going to take a while, so you can sit back and get up to speed on the rest of things while that is in progress. The next thing you need to do is head over to the following thread and read through the first post. You will be following the process for firmware downloaded in xml.zip format: http://xdaforums.com/showthread.php?t=2542219

It sounds to me like you have done at least a solid portion of the prerequisites for this, but you can run through the list to make sure. You might want to download and install the Motorola drivers (Prerequisite 'a') if you haven't already, and you'll want to get the mfastboot-v2.zip package (Prerequisite 'c'). Once you have everything downloaded and the drivers/adb/fastboot stuff installed, the basic idea here is that we are going to take the original stock firmware piece by piece and manually install it using the phone's fastboot mode. If it works correctly, it will completely replace whatever corrupted ROM and recovery files are on your device presently and may allow you to actually boot up the phone into Android 4.4.4 KitKat at a factory default condition.

Find and locate the place where you installed adb and fastboot. On my own system, I just installed it to "C:\adb" for simplicity. In the folder, you'll see adb.exe, fastboot.exe, etc. Take the mfastboot-v2.zip you downloaded above and extract the contents into the same folder -- you should now also have a "mfastboot.exe" file there, as well. Finally, take the stock firmware zip file you downloaded from the above link and extract this into the same folder (make sure all these files are actually in the same folder as the .exe's, not in some subfolder); it contains a good dozen or so files that we are going to flash onto your phone.

In Windows, if you're in the folder with the above files and you hold down the Shift key and right click somewhere in the folder, you'll have an option from the drop down menu to "Open command window here" which should get you a nice command prompt right where you need to be. Get your phone rebooted into fastboot mode, connect it to your PC, and then we can start running through the commands if everything is working correctly.

On the post I linked above, there is a series of mfastboot commands you will have to enter one by one and confirm that it returns an [OKAY] message afterward. The only variation you should have from the original post is that you need to enter an additional command for sparsechunk4 (make sure you scroll this whole list):

mfastboot flash partition gpt.bin
mfastboot flash motoboot motoboot.img
mfastboot flash logo logo.bin
mfastboot flash boot boot.img
mfastboot flash recovery recovery.img
mfastboot flash system system.img_sparsechunk1
mfastboot flash system system.img_sparsechunk2
mfastboot flash system system.img_sparsechunk3
mfastboot flash system system.img_sparsechunk4
mfastboot flash modem NON-HLOS.bin
mfastboot erase modemst1
mfastboot erase modemst2
mfastboot flash fsg fsg.mbn
mfastboot erase cache
mfastboot erase userdata
mfastboot reboot

If everything went well, you should be rebooted into a stock Verizon 4.4.4 ROM. Take your time, let me know if you have any additional questions about the steps or you get stuck, and good luck!