[G 2014 General] zoomingrocket:
Tried both ways, locked & unlocked bootloader but could not have successful flash.

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe oem lock begin
...
(bootloader) Ready to flash signed images

OKAY [ 0.047s]
finished. total time: 0.047s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash partition gpt.bin
target max-sparse-size: 256MB
sending 'partition' (32 KB)...
OKAY [ 0.031s]
writing 'partition'...
(bootloader) Preflash validation failed
FAILED (remote failure)
finished. total time: 0.390s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash motoboot motoboot.img
target max-sparse-size: 256MB
sending 'motoboot' (2184 KB)...
OKAY [ 0.140s]
writing 'motoboot'...
(bootloader) flashing tz ...
(bootloader) flashing rpm ...
(bootloader) flashing sdi ...
(bootloader) flashing aboot ...
(bootloader) flashing sbl1 ...
OKAY [ 1.407s]
finished. total time: 1.547s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash logo logo.bin
target max-sparse-size: 256MB
sending 'logo' (417 KB)...
OKAY [ 0.078s]
writing 'logo'...
OKAY [ 0.109s]
finished. total time: 0.187s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash boot boot.img
target max-sparse-size: 256MB
sending 'boot' (10200 KB)...
OKAY [ 0.499s]
writing 'boot'...
(bootloader) Preflash validation failed
FAILED (remote failure)
finished. total time: 1.014s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash recovery recovery.img
target max-sparse-size: 256MB
sending 'recovery' (10280 KB)...
OKAY [ 0.515s]
writing 'recovery'...
OKAY [ 1.076s]
finished. total time: 1.607s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash system system.img_sparsechunk.0
target max-sparse-size: 256MB
sending 'system' (253883 KB)...
OKAY [ 10.664s]
writing 'system'...
(bootloader) Invalid signed image
(bootloader) Preflash validation failed
FAILED (remote failure)
finished. total time: 11.116s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash system system.img_sparsechunk.1
target max-sparse-size: 256MB
sending 'system' (243637 KB)...
OKAY [ 10.267s]
writing 'system'...
(bootloader) Invalid signed image
(bootloader) Preflash validation failed
FAILED (remote failure)
finished. total time: 10.329s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash system system.img_sparsechunk.2
target max-sparse-size: 256MB
sending 'system' (257347 KB)...
OKAY [ 10.818s]
writing 'system'...
(bootloader) Invalid signed image
(bootloader) Preflash validation failed
FAILED (remote failure)
finished. total time: 10.896s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash system system.img_sparsechunk.3
target max-sparse-size: 256MB
sending 'system' (11724 KB)...
OKAY [ 0.593s]
writing 'system'...
(bootloader) Invalid signed image
(bootloader) Preflash validation failed
FAILED (remote failure)
finished. total time: 0.655s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash modem NON-HLOS.bin
target max-sparse-size: 256MB
sending 'modem' (49252 KB)...
OKAY [ 2.155s]
writing 'modem'...
OKAY [ 2.590s]
finished. total time: 4.744s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe erase modemst1
erasing 'modemst1'...
OKAY [ 0.031s]
finished. total time: 0.031s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe erase modemst12
erasing 'modemst12'...
(bootloader) Invalid partition name modemst12
FAILED (remote failure)
finished. total time: 0.047s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe erase modemst2
erasing 'modemst2'...
OKAY [ 0.062s]
finished. total time: 0.078s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe flash fsg fsg.mbn
target max-sparse-size: 256MB
sending 'fsg' (718 KB)...
OKAY [ 0.125s]
writing 'fsg'...
OKAY [ 0.125s]
finished. total time: 0.265s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe erase cache
erasing 'cache'...
OKAY [ 0.078s]
finished. total time: 0.078s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe erase userdata
erasing 'userdata'...
OKAY [ 0.546s]
finished. total time: 0.562s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe oem lock
...
(bootloader) sst lock failure!
OKAY [ 0.031s]
finished. total time: 0.047s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>E:\MOBILE\MotoG_2ndGen\mfastboot-v2
\mfastboot.exe reboot
rebooting...

finished. total time: 0.000s

E:\MOBILE\MotoG_2ndGen\Stock_Blur_Version.21.11.17.titan_retuaws.retuaws.en.US\R
ETUAWS_XT1064_4.4.4_KXB21.85-17_cid9_CFC.xml>

Any help? On phone screen it says Invalid PIV Image, system downgrade kind of message when sparse files are flashed.