Thank you Tobias and other folks and really sorry for delayed reply on this.
This is what I did:-
- Updated motherboard BIOS version to latest one.
- Verified ISO file should be same as downloaded one, it was corrupted so corrected later.
By doing so, I was able to see Qubes 4.2.0 RC4 installation UI, but was not able to resolve issue of Installation source, so I decided to use Rufus made USB installation media, for this, when I tried to make USB installation media for “Qubes-R4.2.0-rc4-x86_64.iso” by rufus, I was seeing only UEFI (non CSM) option as follows:-See attachment “4.2.0V.png”
but with current stable version of QUBE OS “Qubes-R4.1.2-x86_64.iso”, this issue was not replicable:- See attachment “4.1V.png”
To fix this issue, CSM support should be enabled in my motherboard BIOS, but I don’t have any external graphics card and and as per “https://www.asus.com/support/FAQ/1045467”:-
Intel 500 and the latest series of chipsets do not support VBIOS display, so the integrated display does not support legacy boot, use a graphics card that supports VBIOS to enable CSM.
so this means, in Qube OS 4.2.0 iso file, we are forcing to enable CSM, but in 4.1 version , we were not.
I think, We should not force need of CSM support for QUBE OS 4.2.0 version too.
I hope, this helps to understand cause of issue.
Please let me know, if any correction or any information on this please.
Thanks and Regards
Rahul