GNU/Linux Dual-Boot Install on Windows 10 RAID SSD

How Not to Hork Your Windows 10 Install

I recently received a Dell Inspiron 14 5000 convertible laptop (you know, the one where you can fold over the screen and pretend it's a tablet). It is a nice convertible laptop with touchscreen... fast booting, and with 500GB of SSD storage.

Unfortunately, DELL shipped it with Windows 10 (ugh!) and the SSD configured as RAID. As more experienced users of free software know, the biggest hurdle in configuring a dual-boot system infected with Windows is swapping the storage management from a RAID configuration to AHCI. There are all sorts of bad web sites and posts with bad info regarding this issue. 

But it must be done because GNU/Linux cannot run its installer [specifically partitioning tools] for a dual-boot system on an existing RAID-configured Windows 10 system. The idea is to change the scheme, then use Windows to partion the disk, then run the GNU/Linux install.

Here's how to do the storage management scheme swap and not hork your Windows 10 install.

And fortunately, Dell includes a factory restore mechanism in its Inspiron laptops: If you do run into problems, recover this laptop to its original factory condition by pressing F12 at the Dell logo, then selecting the restore option.

Ok, to begin:

1. run msconfig.exe and set boot to Safe Mode
2. boot to Safe Mode, then reboot to the BiOS by tapping F2 at the Dell logo
3. scroll down to System Configuration, then SATA Operation and set to AHCI, apply and exit
4. boot to Safe Mode, and run msconfig.exe again to set normal boot
5. keep your fingers crossed (it worked on this Dell 14 5000)

Next, make room for GNU/Linux by using the Windows+X key, select Disk Management, select OS (C:) and shrink it (i used 200GB, which is more than enough for GNU/Linux).

My next step was to use Rufus to make a bootable Ubuntu USB using the very latest Desktop version (Ubuntu 18.04.2 LTS, good thru 2023). I popped it into a slot, then rebooted to BIOS, went to General->Boot Sequence, changed the Boot order to the USB drive, applied changes and exited.

Booted to Ubuntu live. Everything worked: sound, network, backlight keyboard, display brightness, touchpad, etc.

Clicked on the install icon on the Desktop, then selected to install a dual-boot system, with Ubuntu installing the GRUB boot loader to offer GNU/Linux or Windows boot. The empty disk space was recognized as partition7 and I assigned it as root ('/') - no fancy partitioning schemes needed for me. And the Ubuntu installer automagically created a 2GB file swap on the SSD and activated it on first boot - very nice, and quite acceptable practice nowadays (no separate swap partition is needed for simple user applications).
 
GNU/Linux was then installed and rebooted; saw the GRUB bootloader screen with Ubuntu first and Windows second. Both work fine!

Hope this helps someone out there.