[Moto G5 Plus ROMs, Kernels, Recoveries, & Other De] PSMDRT:
Thanks [MENTION=2001582]acejavelin[/MENTION]

I've tried that. Here's the output. Please go through it.

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot oem fb_mode_set
< waiting for device >
...
OKAY [ 0.005s]
finished. total time: 0.005s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash partition gpt.bin
target reported max download size of 536870912 bytes
sending 'partition' (45 KB)...
OKAY [ 0.000s]
writing 'partition'...
(bootloader) Validating 'gpt.default.xml'
(bootloader) Committing 'gpt.default.xml'
(bootloader) - flashing 'gpt_main0.bin' to 'partition:0'
(bootloader) Flashing primary GPT image...
(bootloader) Flashing backup GPT image...
OKAY [ 0.156s]
finished. total time: 0.156s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.165s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.447s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.450s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.469s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.173s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.455s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.469s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.453s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.453s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.453s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.183s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
(bootloader) Preflash validation failed
(bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)
finished. total time: 0.466s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot reboot-bootloader
rebooting into bootloader...
OKAY [ 0.016s]
finished. total time: 0.016s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash logo logo.bin
target reported max download size of 536870912 bytes
sending 'logo' (2186 KB)...
OKAY [ 0.078s]
writing 'logo'...
OKAY [ 0.078s]
finished. total time: 0.156s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash boot boot.img
target reported max download size of 536870912 bytes
sending 'boot' (16384 KB)...
OKAY [ 0.538s]
writing 'boot'...
(bootloader) Image signed with key bad key
OKAY [ 0.319s]
finished. total time: 0.857s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash recovery recovery.img
target reported max download size of 536870912 bytes
sending 'recovery' (20580 KB)...
OKAY [ 0.679s]
writing 'recovery'...
(bootloader) Image signed with key bad key
OKAY [ 0.423s]
finished. total time: 1.103s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash dsp adspso.bin
target reported max download size of 536870912 bytes
sending 'dsp' (16384 KB)...
OKAY [ 0.532s]
writing 'dsp'...
OKAY [ 0.176s]
finished. total time: 0.708s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash oem oem.img
target reported max download size of 536870912 bytes
sending 'oem' (94831 KB)...
OKAY [ 3.031s]
writing 'oem'...
OKAY [ 0.761s]
finished. total time: 3.792s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash system system.img_sparsechunk.0
target reported max download size of 536870912 bytes
sending 'system' (517379 KB)...
OKAY [ 16.550s]
writing 'system'...
OKAY [ 4.157s]
finished. total time: 20.707s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash system system.img_sparsechunk.0
target reported max download size of 536870912 bytes
sending 'system' (517379 KB)...
OKAY [ 16.516s]
writing 'system'...
OKAY [ 4.107s]
finished. total time: 20.623s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash system system.img_sparsechunk.1
target reported max download size of 536870912 bytes
sending 'system' (500979 KB)...
OKAY [ 16.032s]
writing 'system'...
OKAY [ 4.019s]
finished. total time: 20.051s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash system system.img_sparsechunk.2
target reported max download size of 536870912 bytes
sending 'system' (523539 KB)...
OKAY [ 16.727s]
writing 'system'...
OKAY [ 3.677s]
finished. total time: 20.404s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash system system.img_sparsechunk.3
target reported max download size of 536870912 bytes
sending 'system' (506655 KB)...
OKAY [ 16.179s]
writing 'system'...
OKAY [ 3.862s]
finished. total time: 20.042s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash system system.img_sparsechunk.4
target reported max download size of 536870912 bytes
sending 'system' (444811 KB)...
OKAY [ 14.171s]
writing 'system'...
OKAY [ 3.432s]
finished. total time: 17.604s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash modem NON-HLOS.bin
target reported max download size of 536870912 bytes
sending 'modem' (75160 KB)...
OKAY [ 2.421s]
writing 'modem'...
OKAY [ 0.642s]
finished. total time: 3.063s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot erase modemst1
erasing 'modemst1'...
OKAY [ 0.016s]
finished. total time: 0.016s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot erase modemst2
erasing 'modemst2'...
OKAY [ 0.031s]
finished. total time: 0.031s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash fsg fsg.mbn
target reported max download size of 536870912 bytes
sending 'fsg' (2500 KB)...
OKAY [ 0.084s]
writing 'fsg'...
OKAY [ 0.075s]
finished. total time: 0.162s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot erase cache
erasing 'cache'...
OKAY [ 0.016s]
finished. total time: 0.016s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot erase userdata
erasing 'userdata'...
OKAY [ 0.041s]
finished. total time: 0.041s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot oem fb_mode_clear
...
OKAY [ 0.016s]
finished. total time: 0.016s

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot reboot
rebooting...

finished. total time: 0.016s

G:\SOFTWARE\Herramientas ADB\platform-tools>

Please correct me if I wrong as I am quite new to these. But, if you see, the chunks were being flashed without any errors or exceptions. But, the third step of the code is what seems the issue as the output has some failures shown.

Here's it again.

G:\SOFTWARE\Herramientas ADB\platform-tools>fastboot flash bootloader bootloader.img
target reported max download size of 536870912 bytes
sending 'bootloader' (5115 KB)...
OKAY [ 0.172s]
writing 'bootloader'...
(bootloader) Validating 'bootloader.default.xml'
(bootloader) Security version downgrade
(bootloader) Image tz failed validation
[COLOR="Red"](bootloader) Preflash validation failed[/COLOR]
[COLOR="red"](bootloader) Security version downgrade
(bootloader) Image devcfg failed validation
(bootloader) Preflash validation failed
(bootloader) Cancelling 'bootloader.default.xml'
FAILED (remote failure)[/COLOR]
finished. total time: 0.453s

I've tried this multiple times. There seems to be no change in the output. As soon as I execute the last step fastboot reboot, the device wouldn't reboot.