[Mi 3 Q&A, Help & Troubleshooting] marioyo:
unfortunately no luck following your exact process. still reboots with the same problems, seems as if the new rom has not been flashed, nor the partitions erased.

This is the logfile from MiFlash

[00001CD0]CreateManagedObject(1392): Unspecified error(0x80131604)
[00001CD0]GetFactoryObject(1436): Unspecified error(0x80131604)
[00001CD0]CreateManagedObject(1392): Unspecified error(0x80131604)
[00001CD0]GetFactoryObject(1436): Unspecified error(0x80131604)
[00001CD0]GetFactoryObject(1457): The specified service does not exist.(0x800704db)
[00001CD0]GetSearchPath(1512): The specified service does not exist.(0x800704db)
[00001CD0]StartFlash(13): The parameter is incorrect.(0x80070057)
[000007DC]bba556b	0.00	execute C:\a\flash_all.bat
[000007DC]bba556b	0.05
[000007DC]bba556b	0.05	$fastboot -s bba556b getvar product 2>&1 | findstr /r /c:"^product: *MSM8974" || echo Missmatching image and device
[000007DC]bba556b	0.27	product: MSM8974
[000007DC]bba556b	0.27
[000007DC]bba556b	0.27	$fastboot -s bba556b getvar product 2>&1 | findstr /r /c:"^product: *MSM8974" || exit /B 1
[000007DC]bba556b	0.31	product: MSM8974
[000007DC]bba556b	0.31
[000007DC]bba556b	0.31	$fastboot -s bba556b getvar board_version 2>&1 | findstr /r /c:"^board_version: *4.4" && echo Missmatching board version
[000007DC]bba556b	0.36
[000007DC]bba556b	0.36	$fastboot -s bba556b getvar board_version 2>&1 | findstr /r /c:"^board_version: *4.4" && exit /B 1
[000007DC]bba556b	0.41
[000007DC]bba556b	0.41	$fastboot -s bba556b getvar board_version 2>&1 | findstr /r /c:"^board_version: *5.[0-9]" && echo Missmatching board version
[000007DC]bba556b	0.45
[000007DC]bba556b	0.45	$fastboot -s bba556b getvar board_version 2>&1 | findstr /r /c:"^board_version: *5.[0-9]" && exit /B 1
[000007DC]bba556b	0.50
[000007DC]bba556b	0.50	$fastboot -s bba556b flash partition C:\a\images\gpt_both0.bin ||
[000007DC]bba556b	0.58	target reported max download size of 1610612736 bytes
[000007DC]bba556b	0.58	sending 'partition' (33 KB)...
[000007DC]bba556b	0.58	OKAY [ 0.004s]
[000007DC]bba556b	0.58	writing 'partition'...
[000007DC]bba556b	0.58	OKAY [ 0.028s]
[000007DC]bba556b	0.58	finished. total time: 0.032s
[000007DC]bba556b	0.58
[000007DC]bba556b	0.58	$fastboot -s bba556b flash tz C:\a\images\tz.mbn
[000007DC]bba556b	0.66	target reported max download size of 1610612736 bytes
[000007DC]bba556b	0.66	sending 'tz' (325 KB)...
[000007DC]bba556b	0.66	OKAY [ 0.012s]
[000007DC]bba556b	0.66	writing 'tz'...
[000007DC]bba556b	0.66	OKAY [ 0.012s]
[000007DC]bba556b	0.66	finished. total time: 0.024s
[000007DC]bba556b	0.66
[000007DC]bba556b	0.66	$fastboot -s bba556b flash dbi C:\a\images\sdi.mbn
[000007DC]bba556b	0.70	target reported max download size of 1610612736 bytes
[000007DC]bba556b	0.70	sending 'dbi' (11 KB)...
[000007DC]bba556b	0.70	OKAY [ 0.004s]
[000007DC]bba556b	0.70	writing 'dbi'...
[000007DC]bba556b	0.70	OKAY [ 0.004s]
[000007DC]bba556b	0.70	finished. total time: 0.008s
[000007DC]bba556b	0.70
[000007DC]bba556b	0.70	$fastboot -s bba556b flash sbl1 C:\a\images\sbl1.mbn
[000007DC]bba556b	0.78	target reported max download size of 1610612736 bytes
[000007DC]bba556b	0.78	sending 'sbl1' (274 KB)...
[000007DC]bba556b	0.78	OKAY [ 0.012s]
[000007DC]bba556b	0.78	writing 'sbl1'...
[000007DC]bba556b	0.78	OKAY [ 0.008s]
[000007DC]bba556b	0.78	finished. total time: 0.020s
[000007DC]bba556b	0.78
[000007DC]bba556b	0.78	$fastboot -s bba556b flash rpm C:\a\images\rpm.mbn
[000007DC]bba556b	0.84	target reported max download size of 1610612736 bytes
[000007DC]bba556b	0.84	sending 'rpm' (185 KB)...
[000007DC]bba556b	0.84	OKAY [ 0.008s]
[000007DC]bba556b	0.84	writing 'rpm'...
[000007DC]bba556b	0.84	OKAY [ 0.008s]
[000007DC]bba556b	0.84	finished. total time: 0.016s
[000007DC]bba556b	0.84
[000007DC]bba556b	0.84	$fastboot -s bba556b flash aboot C:\a\images\emmc_appsboot.mbn
[000007DC]bba556b	1.02	target reported max download size of 1610612736 bytes
[000007DC]bba556b	1.02	sending 'aboot' (2095 KB)...
[000007DC]bba556b	1.02	OKAY [ 0.068s]
[000007DC]bba556b	1.02	writing 'aboot'...
[000007DC]bba556b	1.02	OKAY [ 0.040s]
[000007DC]bba556b	1.02	finished. total time: 0.108s
[000007DC]bba556b	1.02
[000007DC]bba556b	1.02	$fastboot -s bba556b reboot-bootloader
[000007DC]bba556b	1.05	rebooting into bootloader...
[000007DC]bba556b	1.05	OKAY [ 0.000s]
[000007DC]bba556b	1.05	finished. total time: 0.000s
[000007DC]bba556b	1.06
[000007DC]bba556b	1.06	$ping 127.0.0.1 -n 5 -w 1000 1>nul
[000007DC]bba556b	5.14
[000007DC]bba556b	5.14	$fastboot -s bba556b erase boot
[000007DC]bba556b	5.19	erasing 'boot'...
[000007DC]bba556b	5.19	OKAY [ 0.004s]
[000007DC]bba556b	5.19	finished. total time: 0.004s
[000007DC]bba556b	5.19
[000007DC]bba556b	5.19	$fastboot -s bba556b erase DDR
[000007DC]bba556b	8.33	erasing 'DDR'...
[000007DC]bba556b	8.33	OKAY [ 3.098s]
[000007DC]bba556b	8.33	finished. total time: 3.098s
[000007DC]bba556b	8.33
[000007DC]bba556b	8.33	$fastboot -s bba556b flash misc C:\a\images\misc.img
[000007DC]bba556b	8.38	target reported max download size of 1610612736 bytes
[000007DC]bba556b	8.38	sending 'misc' (8 KB)...
[000007DC]bba556b	8.38	OKAY [ 0.004s]
[000007DC]bba556b	8.38	writing 'misc'...
[000007DC]bba556b	8.38	OKAY [ 0.004s]
[000007DC]bba556b	8.38	finished. total time: 0.008s
[000007DC]bba556b	8.38
[000007DC]bba556b	8.38	$fastboot -s bba556b flash modem C:\a\images\NON-HLOS.bin
[000007DC]bba556b	11.13	target reported max download size of 1610612736 bytes
[000007DC]bba556b	11.13	sending 'modem' (54385 KB)...
[000007DC]bba556b	11.13	OKAY [ 1.705s]
[000007DC]bba556b	11.13	writing 'modem'...
[000007DC]bba556b	11.13	OKAY [ 0.957s]
[000007DC]bba556b	11.13	finished. total time: 2.661s
[000007DC]bba556b	11.14
[000007DC]bba556b	11.14	$fastboot -s bba556b flash system C:\a\images\system.img
[000007DC]bba556b	84.39	target reported max download size of 1610612736 bytes
[000007DC]bba556b	84.39	erasing 'system'...
[000007DC]bba556b	84.39	OKAY [ 0.004s]
[000007DC]bba556b	84.39	sending 'system' (1265949 KB)...
[000007DC]bba556b	84.39	OKAY [ 39.929s]
[000007DC]bba556b	84.39	writing 'system'...
[000007DC]bba556b	84.39	OKAY [ 27.665s]
[000007DC]bba556b	84.39	finished. total time: 67.599s
[000007DC]bba556b	84.48
[000007DC]bba556b	84.48	$fastboot -s bba556b flash cache C:\a\images\cache.img
[000007DC]bba556b	84.98	target reported max download size of 1610612736 bytes
[000007DC]bba556b	84.98	erasing 'cache'...
[000007DC]bba556b	84.98	OKAY [ 0.008s]
[000007DC]bba556b	84.98	sending 'cache' (8336 KB)...
[000007DC]bba556b	84.98	OKAY [ 0.260s]
[000007DC]bba556b	84.98	writing 'cache'...
[000007DC]bba556b	84.98	OKAY [ 0.168s]
[000007DC]bba556b	84.98	finished. total time: 0.436s
[000007DC]bba556b	84.98
[000007DC]bba556b	84.98	$fastboot -s bba556b flash userdata C:\a\images\userdata.img
[000007DC]bba556b	127.63	target reported max download size of 1610612736 bytes
[000007DC]bba556b	127.63	erasing 'userdata'...
[000007DC]bba556b	127.63	OKAY [ 1.504s]
[000007DC]bba556b	127.63	sending 'userdata' (731686 KB)...
[000007DC]bba556b	127.63	OKAY [ 23.077s]
[000007DC]bba556b	127.63	writing 'userdata'...
[000007DC]bba556b	127.63	OKAY [ 14.818s]
[000007DC]bba556b	127.64	finished. total time: 39.399s
[000007DC]bba556b	127.74
[000007DC]bba556b	127.74	$fastboot -s bba556b flash recovery C:\a\images\recovery.img
[000007DC]bba556b	128.61	target reported max download size of 1610612736 bytes
[000007DC]bba556b	128.61	sending 'recovery' (15652 KB)...
[000007DC]bba556b	128.61	OKAY [ 0.492s]
[000007DC]bba556b	128.61	writing 'recovery'...
[000007DC]bba556b	128.61	OKAY [ 0.280s]
[000007DC]bba556b	128.61	finished. total time: 0.772s
[000007DC]bba556b	128.61
[000007DC]bba556b	128.61	$fastboot -s bba556b flash boot C:\a\images\boot.img
[000007DC]bba556b	129.44	target reported max download size of 1610612736 bytes
[000007DC]bba556b	129.44	sending 'boot' (14386 KB)...
[000007DC]bba556b	129.44	OKAY [ 0.452s]
[000007DC]bba556b	129.44	writing 'boot'...
[000007DC]bba556b	129.44	OKAY [ 0.256s]
[000007DC]bba556b	129.44	finished. total time: 0.708s
[000007DC]bba556b	129.44
[000007DC]bba556b	129.44	$fastboot -s bba556b reboot
[000007DC]bba556b	129.47	rebooting...
[000007DC]bba556b	129.47
[000007DC]bba556b	129.47	finished. total time: -0.000s
[000007DC]bba556b	129.50
[000007DC]GetFactoryObject(1457): The specified service does not exist.(0x800704db)
[000007DC]SaveFlashResult(1478): The specified service does not exist.(0x800704db)