I recently purchased a Terramaster F8 Plus, which is an all NVMe NAS.
I was able to install TrueNAS 25.04.0 by disabling the VT-d option in the bios.
Recently, I discovered a thread mentioning that adding pci=nommconf to the grub.cfg allows VT-d to be enabled. After some research, I created /boot/grub/custom.cfg using nano and added ‘set pci=nommconf’ (without quotes) to see if I could enable VT-d. My understanding is that parameters listed in custom.cfg are added to grub.cfg when it is rebuilt, but I’m not sure when a rebuild occurs.
It appears that adding ‘set pci=nommconf’ to custom.cfg did not work since TrueNAS crashes as soon as it attempts to list the disks when creating a pool.
Does TrueNAS automatically rebuild grub.cfg when it reboots, or is there something else that I should try?
If you’re trying to enable VT-d or need to pass custom kernel parameters like pci=nommconf (useful for fixing NVMe-related crashes when VT-d is enabled), do not edit GRUB manually — it can be overwritten during updates.
Instead, use the built-in midclt command, which safely stores the setting in the system configuration.