Fresh install Windows 10 x64 20H2 Pro, I've done fresh ones before (years ago, Windows 10) with this motherboard which is Asrock H81M R2.0 (circa 2015) So doing a UEFI boot off the USB it showed the asrock logo with the swirl, booted into setup, all is well and for Microsoft account I used offline, and first boot still has Asrock logo loading my little user icon was Asrock and the wallpaper was too! Is this something new or is it because of UEFI boot as opposed to legacy boot that it is feeding this info to Windows setup?
Aside from the boot screen, the wallpaper and whatnot could have probably synced to your Microsoft account.
Yes you're right, I flashed the USB with MBR and non-UEFI and lo and behold all the branding disappeared. Yay! Thanks See above as I've never has a MS account.