Windows 10: Upgrade fail from 20H2 to 21H1.

I've had problem upgrading my pc .. i couldnt upgrade form 2004 to 20H2 or from 20H2 to 21H1 .. it shows the Windows update and then I download it and then it fails.. and then the update disappears.. and then when I try thru upgrade assistant it fails and rolls back.. and if it manages to succeed then it wont boot/or boot messes up.. I have to either fix efi or I have to clean install it. what could be the problem? The pc is probably a year and half or so. i9 9900k, 64g Ram, aorus master z390 Mb, evo 970 plus 2tb nvme drive.(which was bought like couple of months back) I've attached setupdiag.exe's log .. currently running 20H2. ** Disk 4 is my "old" os drive i.e evo 970 500gb which is wiped.

:)

 

Upgrade to 20H2 failed

The laptop was offered the feature upgrade to Win 10 20H2. It is still running 1903. It had failed 1909, 2004 with this error 0x80004005 - 0x1000A,The installation failed in the DOWNLEVEL phase with an error during PREPARE_FIRST_BOOT operation.

Since Microsoft does not like this laptop anymore I had done a chkdsk, a SFC / scannow and a disk error check from the properties tab. All errors fixed.

I stopped MS secutity, firewall and the Avast security for the upgrade.

Downloading and installing took some time and it looked as if the laptop was going through the motions. At the end it had just reverted to 1903 again.

What else can I do short of a complete reset?

 

Manually install 20H2 prior to 21H1 - possible?

Hi all - I procrastinate installing major updates to my systems, and I finally installed 20H2 on my desktop a few weeks ago. However, I was just about to install 20H2 on my laptop and saw it is no longer available (only 21H1 in Windows Update). I found a manual download of a 20H2 .msu file that matched my system (x64) (last file listed here) but that would not install, giving me a "not applicable to your computer" error.

Is it simply too late to install 20H2 now that 21H1 is officially released? I'd much rather update to a build I've already used first, but I guess I can just wait another couple months and go straight to 21H1.

I'm currently on Win 10 Pro 2004 x64.

 

How to get the Windows 10 May 2021 Update version 21H1

so to upgrade from 20H2 to 21H1 has two steps:
1. install EP
2. install update, but which one? for x64 arch. thx