I installed Ubuntu 24.04 LTS on the secondary SSD in my Laptop 16. The primary SSD has Windows 11 installed.
I left out the primary SSD after installing the secondary SSD. I used the Framework Laptop 16 replacement guide for the midplate Midplate Replacement to get me started. I also looked at the replacement guide for the main board to locate the the secondary SSD socket (under the primary SSD.)
With just the secondary SSD installed, I booted the laptop using a USB drive formatted with Ubuntu 24.04. I followed the instructions in the Ubuntu Installation Guide . I used a wired internet connection so I did not have any issues with wireless causing installation problems. The installation process went fine. I have not noticed any issues so far.
I re-installed the primary SSD. I changed the boot order as described in the thread Dual Boot problems. I have my system default to Windows for now. I have a lot to learn about Linux in general and the boot process.
I think it would be possible to install Linux on the secondary SSD with both SSD’s installed. One would need to use Advance feature to select the secondary SSD and define a partition table for that SSD. I did not feel confident I could do it correctly, so I choose to install Linux with just the secondary SSD installed.