Inspiron 7490 BIOS: How to turn off intel 'RAID on', and swith disk mode to AHCI?

Update: Already compiled the linux Kernel with Endless OS patches. Trying to figure how to compile ubuntu with the custom kernel. Fingers crossed but should have a working image soon. I'm busy so will try to get that out in the next week or so. 

No thanks Dell

So I have been running ubuntu 20.04 for the 3 weeks. Sorry guys took a while to make this post but you can see the image on sourceforge is almost a month old. Will update this guide with more detailed instructions with time, but you have the general steps. (Talking about the bootloader copying bit). Stackoverflow will tell you how to mount the boot partition and copy stuff, then unmount.

All seems okay, just been lazy to post the guide, but for the brave hearts, here's the image

https://sourceforge.net/projects/ubuntu-raid/files/Ubuntu-Raid-5.60-7-generic/

After installing it you must fix the bootloader. So the instructions for doing that- I didn't document the commands to the last bit but I will post general instructions on how I did it. Rest assured, it's super easy and it is highly unlikely you will end up with a damaged windows boot

1. After installing with this cd, you have to still boot into the installer on pendrive not your harddrive

2. Don't waste time trying to autofix grub, it doesn't work. All instructions you will find online will waste your time.

3. Go to SuperGrub and download the standalone EFI image. 

4. Copy this image to anywhere on your boot partition

5. Reboot and enter BIOS settings

6. Add a boot option within the firmware, give it a name and for the image location, it will open a file picker, you can navigate to your boot partion from here and select the supergrub image you copied

7. (Optional) Can reorder your boot options so that this option it the first

SUCCESS

Note: - whenever you boot, supergrub always detects installed OS's on your system and provide a list you can select from. This means it is sort of bullet proof since it does this detection on boot (fast). Thus regardless of how many OS's you'd like to boot, they will always be autodetected and you don't have to change/fix your bootloader again.

Can boot into both windows and Ubuntu from this

For ubuntu, always select the 5.6 kernel from the boot options every time you are booting, that is the new kernel I compiled with the RAID fixes, the 5.4 won't boot.

8. On first boot, you want to pin the kernel version so that it is never updated on update check. Run `sudo apt-  mark hold 5.6.0-7-generic`

Wow great job, I have it running on my laptop, thank you very much ! (and thank you for the askubuntu post, really well documented and updated!)

Thank you so much @evroza , works great ! 
The superGrub works fine, I even did not messed my Windows setup.

Ubuntu and all my environment is working fine, I can now use my laptop as I intended.
The only thing wrong is that it's a laptop with "Prime" or "Optimus" graphics drivers due to Nvidia&Intel graphics, and I can't get Vsync with my nvidia driver (Open Xorg or nvidia sourced), and by following few tips to force vsync on prime laptops, I made Ubuntu unabled to boot. Had to reinstall Ubuntu 3 times each time I screwed it.

But anyway except this vsync issue, everything is working great. Thank you a lot.

Congratulation @evroza on this success.

However, I am stuck like Jeroen_ at 'Could not open "\EFI\BOOT\fallback.efi": 14'

It does not install. Can you help ?

Hi guys, so can't edit original post.

If you're experiencing the error 'Could not open "\EFI\BOOT\fallback.efi": 14' when trying to Install it's because the image was not properly flashed to USB. THe software you used matters. I would recommend Rufus on Windows.

For the copying of the Supergrub image while in live usb:

1. Open terminal and run sudo fdisk -l

That will list the partitions on your hard drive and you'll be able to locate the boot partion, it should be the one with Type 'EFI System'

2. make a directory to mount the boot partition: sudo mkdir /mnt/efi

3. Mount the boot partion from step 1 to the directory we just created. In this case it would be sudo mount /dev/nvme0n1p1 /mnt/efi

4. List content: ls /mnt/efi should have a Boot directory in there

5. Can copy the supergrub image anywhere in here. Let's put it in the EFI/Boot directory. So mv you/super/grub.EFI /mnt/efi/EFI/Boot/super_grub.EFI

6. Unmount and reboot. sudo unmount /mnt/efi

7. Enter BIOS settings and select Boot Options

8. Add Boot option, navigate to Boot partition which should be first in the list of file picker and select the super_grub.EFI we copied. Give it a name and reorder boot options so that this option is first

9. On reboot Supergrub will open. Should select first option. 'Detect and show boot methods'. Select kernel 5.6.0-7-generic 

10. If want to boot into windows from supergrub the select 'bootmgfw.EFI'. Note that the old windows boot entry still exists. So if you wish to use that instead of supergrub you just need to reorder boot options in BIOS settings.

Images above not posted in right order. But you get the idea. Also about the Vsync issue. I think I am also experiencing the same problem. Sometimes the UI freezes for a few seconds. But it's something I can live with. If someone solves it then post back with procedure. Not willing to attempt it on my machine at the moment since I have a lot of work in Ubuntu. So anyone with a new install can try.

You are a champion @evroza ! It has come a few days too late for me unfortunately. I wasted many, many hours trying to get VirtualBox and then VMware working before finally biting the bullet and spending 150$ to upgrade to Windows Pro so I could get a usable Linux. Windows is broken for everything except HyperV these days... With WSL2 and a full Ubuntu in Hyper-V I am going to call it quits until my next machine I think. Needless to say, it won't be a Dell... 

Wow, after using Rufus instead of dd command to copy "Ubuntu-Raid-5.60-7-generic/custom-dist.iso" to a usb stick I could boot from it and was successfully able to install Ubuntu 20.04!

However unfortunately can't get SuperGrub to work on Inspiron 7490. After selecting SuperGrub boot option it gives 2 loud ticks over the speaker while Dell recovey takes over and starts checking the system.

Am using bios v1.4.1, have tried renaming 'super_grub2_disk_standalone_x86_64_efi_2.04s1.EFI' to 'super_grub.efi' and placing it in EFI/Boot. Also tried placing 'super_grub2_disk_hybrid_2.04s1.iso' and 'supergrub2-2.04s2-beta2-multiarch-USB.img' on usb stick using Rufus and booting from it. Also tried disabling Bitlocker drive encryption. Also tried disabling Safe Boot. Also tried resetting Bios settings. Any tips?

Thank you evroza,

I can boot into Ubuntu.

Trying to boot into W leads to a recovery mode. Fortunately I made a recovery USB Stick and I'll try that.

@Jeroen-  not sure why that would be since I haven't encountered problems with the supergrub. But you'd have to confirm supergrub actually works for you before trying to use it as a bootloader. Download the supergrub iso image and flash it to usb. Verify that you are able to boot into ubuntu using this rescue USB.

If that works then there's no reason the EFI to boot partition shouldn't, it's the same thing. However, if you can't use this rescue image to boot into your ubuntu then there's a problem with you install and might have to reinstall or explore other solutions

Supergrub is working now on Inspiron 7490 after disabling Secure Boot in Bios. Thanks so much for all the help everybody, especially evroza. It's unbelievable that this day has arrived Time to enjoy Ubuntu 20.04!

I've just finished configuring ubuntu using @evroza 's method. Everything went pretty well. Almost a year has passed, I almost lost the last hope and, finally, the solution is presented!

Wanted to mention that Dell did nothing to help to resolve the problem. In my opinion, it's a shame.

Thanks a lot @evroza ! You are my hero!

Also I have a little question to clarify. When I run the command sudo apt-mark showhold in the shell the output is

linux-generic
linux-image-5.6.0-7-generic
linux-image-generic

Does it mean that now I shouldn't be afraid to run apt update or apt upgrade? What should I do to avoid updating distro version?