Cannot access the grub after adding an NVME

I just installed an NVMe on my machine. I previously had a dual-boot on the same SSD and the grub allowed me to switch. I decided to install an nvme on which I was going to put a second OS but the concern is that it is not possible for me to access the Grub (nor any boot) of my old SSD when the NVMe is plugged. So impossible to add my Nvme to the grub. You will have understood that therefore when I remove the NVMe I have access to the grub and therefore to my 2 OS. Do you have any idea what is wrong and if so how do I seem to fix it? thank you in advance

I’d Suggest check your bios at startup and make sure the nvme is not set to the 1st boot device.If is is set the ssd to the 1st and the nvme to the 2nd

I know but that doesn’t work ^^! I’m trying to boot from my old SSD. But no way, no sign of life. Worse, the bios loops.

I don’t know what kind of a motherboard you have but on one computer I have set up it can not use nvme it can only use an m2 ssd.

My nvme is working perfectly. Because since I couldn’t go to the grub, I already installed my second OS on the nvme.

I have an AORUS B450 Elite

I have the same motherboard on another computer and your right as i have an nvme set up.It looks like your going to have to redo your grub.You can search the forum or maybe someone can help you better sorry I don’t have anything set up as dual boot.

Redo a grub ok but it is impossible for me to access my old SSD. Even through a liveCD. That’s what I don’t understand … So I can’t redo my grub if I don’t have access to my Manjaro machine

Are you aware that using m.2 sockets results in blocking specific sata ports?
(source: motherboard manual 1-7 Internal Connectors)