Feature update to Windows 10, version 1709 fails to install

(1) That's getting pretty bad, when the computer tells you its system files are corrupt. The only thing, really, that can cure system files are system files.

(a) One cure is an upgrade-install, but we're already having fun doing that.

(b) Try the DISM & SFC duo, in that order, but often they prove to be inadequate, saying there is nothing to fix or saying they did fix it - but still the problem remains...!...

https://support.microsoft.com/en-us/help/929833/use-the-system-file-checker-tool-to-repair-missing-or-corrupted-system

Use the System File Checker tool to repair missing or corrupted system files

And good luck, if they refuse to run or spit out error messages or names of files they can't repair.

(2) Yes

• the ISO or Installation media must match or exceed the OS version that is installed. (The same is true of the Recovery drive.) Yours qualifies. But you can't boot to an ISO unless you burn it to a DVD. You need to boot to it to get to the "Repair this computer" option that will go to the recovery environment. So, either burn that to a DVD (right-click the ISO for the option to burn it) or go back & make a USB version...

https://www.microsoft.com/en-us/software-download/windows10

Download Windows 10 -  Currently, this is version 1709

That is version 1709 now - not v.1703.

(3) Maybe try to make a Recovery DVD (Repair Disc), at "START, Settings, Update & Security, Backup, Go to Backup & Restore (Win 7)" (or ask Cortana for Control Panel, & select Backup & Restore)...

(4) At your ROG site, I think I see it is the ESC key that will get to your UEFI boot options screen. Hold the ESC key as you boot for the boot menu. Then select the DVD or USB Installation media. (Or select the Recovery DVD or USB, if you've been able to make one.) When it starts, remember to click "Repair this computer" at the lower left instead of to install.

If you were brave enough, Robert, you could regenerate your entire BCD with BCDBoot. But - in case of catastrophe - don't tell beerus_king. It might scare him off!

i did try those sfc and dism months ago. there was no error. anyway i did try it again TODAY, here is what i found...

1. DISM

Microsoft Windows [Version 10.0.14393]

(c) 2016 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>DISM.exe /Online /Cleanup-image /Restorehealth

Deployment Image Servicing and Management tool

Version: 10.0.14393.0

Image Version: 10.0.14393.0

[===========================96.6%========================  ]

Error: 0x800f081f

The source files could not be found.

Use the "Source" option to specify the location of the files that are required to restore the feature. For more information on specifying a source location, see http://go.microsoft.com/fwlink/?LinkId=243077.

The DISM log file can be found at C:\WINDOWS\Logs\DISM\dism.log

C:\WINDOWS\system32>

2. sfc

C:\WINDOWS\system32>sfc /scannow

Beginning system scan.  This process will take some time.

Beginning verification phase of system scan.

Verification 100% complete.

Windows Resource Protection found corrupt files and successfully repaired

them. Details are included in the CBS.Log windir\Logs\CBS\CBS.log. For

example C:\Windows\Logs\CBS\CBS.log. Note that logging is currently not

supported in offline servicing scenarios.

C:\WINDOWS\system32>

=== i am pretty surprised. there was no such error before===

whooaaahhh,, what is that? i am scared hahaha... i have no idea what are u guys talking or planning.  (Im no windows 10 expert).

Btw i have posted my sfc and dism results

Yes, I see them. Since SFC fixed something, try DISM once or twice more.

But I think the repair-install is the best bet to cure that. So, make the backup BCD. Then, try making a Repair Disc to get to the recovery environment to have a look. Or download v.1709 to a USB drive.

Etc. - it's all in my posts above. Good luck.

I want to try a BCDBoot of my own - except I'm afraid it will ruin me & I won't be here to help you do yours! 😉.