My Moto G is working again since one week with stock 4.4.2. I had to do it ain a bit different way...
First, I could get into bootloader and recovery. after several hours my pc recognizes my phone again, but till now I don't know why and how.
Wanted to reflash stock 4.4.2 kitkat again, but this won#t work. so I figured out that after unpacking, I had to replace the gpt.bin with the one from the 4.4.4 stock update. (see down as zip file)
Then I flashed the 4.4.2 stock again to my phone and all went well. It started again. (now I'm on stock recovery)
If you want to do the OTA 4.4.4 Update, there have to be a few things on your phone, otherwise update always fails.
1. if you have x-posed frameworks installed - uninstall it completely
2. if rooted, go into super su preferences and activate unroot all
3. do not activate developper options, or if done before, just uncheck the mark
4. you must be on stock recovery!
5. restart your phone
6. now search after update in about phone.
if bootloader is unlocked - doesn't matter - can stay unlocked
with me it first installed the 176.* OTA because my flashed stock was still 175.*
this went well, then again searched for update and 210.* (4.4.4 kitkat) could be downloaded ota. after it was done, click to install and it should work well - took a bit time.
now you are on stock 4.4.4, but without root atm.
if you want root back - now flash the newest twpr recovery 184.108.40.206 to phone, because here an OTG USB stick will be also recognized - OTG cable needed before. (don't need to push files first to phone)
copied before the su.zip to usb stick and sticked it to phone, then go into recovery. here you can install super user or better su.zip. restart phone and you got your root back on 4.4.4 stock kitkat rom