I'm back in Ubuntu! The issue was that the path to grub set in the BIOS after the firmware upgrade was wrong. Fixing the path fixed the issue.
To do this, press the F2 key while rebooting the Dell laptop, to bring up the BIOS interface.
Optional: In the menu on the left, first select System Configuration > SATA Operation, and select the AHCI radio button. (This step is required on my machine, because there are no RAID drivers installed for Ubuntu yet. If you have RAID drivers for Ubuntu, then you can choose RAID On instead.) Confirm the change of SATA Operation.
With the correct SATA setting already chosen, select Boot Sequence, and then click on the Add Boot Option button in the middle of the right pane. Name the new record (in my case — Ubuntu AHCI) and click on the [...] button to the right of the File Name field, choose a grub file for start-up. Select EFI > ubuntu > grub64.efi. Click OK.
Using the arrows by the list at the top right of the Boot Sequence pane, place your new Ubuntu Boot Option at the top of the list.
I had a new Boot Option with an unhelpful name (UEFI: THNSN5256GPU7 NVMe TOSHIBA 256 GB, Par) which had the same choice of file as Windows Boot Manager. I deleted this, and checked afterwards that I could still boot into Windows. Here is what my Boot Options look like now:
[✓] Ubuntu AHCI
[✓] Windows Boot Manager
Click Apply, confirm your changes, and then click Exit.
The machine should now boot into Ubuntu, just as it did before the firmware upgrade.
Steps to install Ubuntu 18.04 alongside pre installed Windows 10 as dual boot in NVMe SSD.
Hardware Information:
- Dell G5 5587
- Core i7 8750H
- RAM 16 GB
- NVMe SSD (Toshiba) 256 GB
- HDD 1 TB
- NVIDIA® GeForce® GTX 1060 6GB GDDR5 with Max-Q Design
Download Files
Burn the ISO to a Pendrive
- Insert a USB pendrive.
- Backup the pendrive data if necessary.
- Open Rufus.
- Select Partition Scheme
MBR.
- Keep the other settings to default. E.g.: FAT.
- Select the ISO and burn it to the connected pendrive.
Create Unallocated Space for Ubuntu
- Open disk management in Windows.
- Shrink the volume where Windows is installed (NVMe SSD). The size depends on yourself. I have created 100 GB of unallocated space.
Turn off Fast startup from Windows 10
- Dual boot does not work when Fast startup option is enabled in Windows 10.
- Right-click the
Start button.
- Click
Search.
- Type
Control Panel and hit Enter on your keyboard.
- Click
Power Options.
- Click
Choose what the power buttons do.
- Click
Change settings that are currently unavailable.
- Uncheck
Turn on fast startup (recommended).
- Click
Save changes.
Turn off secure boot from BIOS
- Tap F2 key at the Dell logo screen to enter System Setup or BIOS.
- On the left pane, click
Boot Sequence.
- Check that Secure Boot is set to Disabled. Within the BIOS go to
Secure Boot > Secure Boot Enable, and set the checkbox to Disabled.
- Change the
Secure Boot Mode to audit mode.
- Save settings and the machine will be restarted.
Enable AHCI for dual boot
- With a preinstalled Windows SATA mode set to IDE or RAID in BIOS.
- To install dual boot we need to change SATA mode to AHCI from BIOS.
- Create the Windows 10 local account:
- Go to Settings > Accounts.
- Select
Family & other users.
- Tap
Add someone else to this PC.
- Select
I don't have this person's sign-in information.
- Select
Add a user without a Microsoft account.
- Enter a username, type the account's password twice, enter a clue and select Next.
- Change the
Account type of this newly created account to Administrator.
- Login using this new user account.
- Right-click the Windows Start Menu. Choose Command Prompt (Admin).
- Type this command and press ENTER:
bcdedit /set {current} safeboot minimal
- Restart the computer and enter BIOS Setup. On Dell Inspiron it is F2.
- Change the
SATA Operation mode to AHCI from either IDE or RAID.
- Save changes and exit Setup and Windows will automatically boot to Safe Mode.
- Right-click the Windows Start Menu once more. Choose Command Prompt (Admin).
- Type this command and press ENTER:
bcdedit /deletevalue {current} safeboot
- Reboot once more and Windows will automatically start with AHCI drivers enabled.
Install Ubuntu
- After the OS burn, insert the pendrive and restart the machine.
- Press F12 or F10 depending your machine.
- Select USB/Removable media.
- Select install Ubuntu.
- Select Language and other options.
- When it comes to partition option, select
something else.
- In the unallocated space:
- Give 2 GB Logical space to swap memory. The swap size depends on your RAM size.
- Give remaining Primary space to
/ partition
- Select
Windows Boot Manager as Device for boot loader installation.
- Continue with the remaining process.
Install Drivers (optional)
- After successful installation of Ubuntu, update the system softwares.
- To update the drivers:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
ubuntu-drivers devices
sudo ubuntu-drivers autoinstall
- You may now access both Windows and Ubuntu in a dual boot manner.
Reference:
Best Answer
My problem was apparently different from the suggested question.
The issue I had was that in AHCI mode, Ubuntu booted and worked normally but Windows did not boot at all. Then I switched to RAID and noticed that Windows booted and worked normally but Ubuntu did not boot at all.
The problem was that I had switched from RAID to AHCI without safe mode in Windows. When I applied the same switch but in safe mode everything worked fine.