Unable to Dualboot (Ubuntu / Windows) with RAID1 Array, NVME M2 SDD & GRUB

Question

I have a problem with the configuration of Dualboot Machine (Ubuntu/Windows) and a Raid1 array (2x HDD 5TB via RST).

I installed Ubuntu on sdd (SATA SDD). Windows was installed on a NVME M2 SDD. The Raid HDDs are sdb & sdc. There is another single HDD (sda) for data storage.

Here's the problem: I am not able to detect the NVME M2 SDD (with the installed Windows) in Ubuntu. Hence GRUB doesn't offer me to choose to boot Windows before booting Ubuntu.

I already researched the problem and found that I'd need to switch Options in my BIOS/UEFI to AHCI. However, if I'd do this, I would get a problem with my Raid Array isn't it? So I'm kind of locked into the Raid-On option in my BIOS/UEFI. I'm wondering whether there is a way to let Ubuntu detect the NVME M2 SDD (with Windows on it) with the RST/Raid-On Option enabled in BIOS/UEFI? If that is not possible: Do you have any idea on how to configure a dual boot option that would let me choose between booting Ubuntu or Windows, besides GRUB?

Here's the lsblk output, showing that no NVME SSD is detected:

micha@micha-XPS-8940:~$ lsblk | grep -v '^loop'
NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
sda           8:0    0 931,5G  0 disk  
├─sda1        8:1    0   128M  0 part  
└─sda2        8:2    0 931,4G  0 part  
sdb           8:16   0   4,5T  0 disk  
├─md126       9:126  0   4,5T  0 raid1 
│ ├─md126p1 259:0    0    16M  0 part  
│ └─md126p2 259:1    0   4,5T  0 part  
└─md127       9:127  0     0B  0 md    
sdc           8:32   0   4,5T  0 disk  
├─md126       9:126  0   4,5T  0 raid1 
│ ├─md126p1 259:0    0    16M  0 part  
│ └─md126p2 259:1    0   4,5T  0 part  
└─md127       9:127  0     0B  0 md    
sdd           8:48   0 465,9G  0 disk  
├─sdd1        8:49   0   200M  0 part  /boot/efi
├─sdd2        8:50   0 195,3G  0 part  /var/snap/firefox/common/host-hunspell
│                                      /
├─sdd3        8:51   0 619,9M  0 part  
├─sdd4        8:52   0 195,3G  0 part  /home
└─sdd5        8:53   0  74,5G  0 part  [SWAP]

Here's the lsmod output, showing that the nvme modules are loaded.

micha@micha-XPS-8940:~$ lsmod | grep nv
nvme                   49152  0
nvme_core             135168  1 nvme

Answer 1

Half a year later I found the answer for this question, when I needed to reinstall Ubuntu.

I needed to create an EFI partition on the harddrive sda and move the bootloader to this hard drive. Once I reconfigured GRUB both Windows and Ubuntu got recognized. Now GRUB loads once I boot my PC and I can choose between booting Ubuntu and Windows. This post helped me to move the bootloader to the right partition and to reconfigure GRUB: https://askubuntu.com/a/1296430/1665605

However I still can't access the NVME SSD via Ubuntu.

Answer 2

Unless you configured your RAID members in UEFI, you're probably using software RAID (as in, a RAID configured in Linux kernel, not in controller firmware). In that case, I don't think you need to switch the disk from AHCI to RAID mode in UEFI. As far as I know, that switch configures how UEFI exposes your disks to the operating system. Setting it to RAID probably enables some legacy protocol, which is likely also slower than AHCI. So, if I myself used software RAID, I would still keep the AHCI setting on, unless it wouldn't work that way.

Also/alternatively, your UEFI likely has a setting to enable a "Boot menu" key (e.g. F12 or such; the key might also be permanently enabled). Assuming Linux continues to fail detecting your Windows drive, you could just use the UEFI's boot menu key to boot to Windows instead of going via Grub.