Dell G5 cannot install Win 10 , cannot boot original HDD Win10 also

Hi there,

I have lots of years in IT but after 3 days of being unable to resolve this problem I am here for help.

Background, I got a DELL G5 with a HDD 1tb Window 10 working perfectly. I ran a couple of Win 10 reset using Dell restore process without any issues.

Important: 

- I updated BIOS to version 1.14.0

- Original 1TB HDD is untouched as it came from manufacture.

- BIOS setting SATA = RAID on, Secure Boot = ON

Here is where the problem started?

(a) I bought a M.2 SSD 512GB and got it installed

(b) I could not install Linux Centos (Red Hat 7.9) until I changed BIOS to SATA = AHCI

(c) Linux was installed on the M.2 drive and works perfected but as you can imagine the BIOS Boot "Windows Manager" stopped working due Win 10 drivers (SATA RAID) ... that is what I understand from all the reading.

(d) To make it simpler - I removed M.2, change SATA back to RAID ==> WIN 10 DOES NOT BOOT

To avoid messing with Original HD from Dell, I replaced with another HD to install Win 10 from scratch. This is what happened:

I wrote win10 image to a 8GB pen drive (tried 2 win10 versions as below) using 4 different methods.

Win10_20H2_English_x64.iso

Win10_1809_English_x64.iso

When boot starts I see the famous Windows image (4 blue squares) and a spinning image looping, never goes to the dialog "Installing Windows".

I tried BIOS changes (secure=off) ... removed bios battery ... always same issue.

Important: I take pen drive and put in a Lenovo X1 Carbon and Windows install dialog works every time. That means windows image is fine ... problem is DELL.

Any help is greatly appreciated.

Borba.