🧨 From Crash to Passthrough: Installing Proxmox VE on a Single-GPU System (No iGPU)

Applies to: Systems with an RTX 3090, no onboard graphics (iGPU), and a goal of GPU passthrough.

If you’re installing Proxmox VE and your system crashes at "Loading drivers: .......", you’re not alone.

This guide builds upon the foundational article “GRUB Parameters for GPU Passthrough – A Comprehensive Guide” and walks you through both:

1. Getting the installer to boot when you only have a single GPU
2. Preparing Proxmox for GPU passthrough after install
3. Installing and configuring Proxmox step by step using a real-world example (Thor)

⚙️ BIOS Settings

🔹 Phase 1 — Installer Crashes at Boot (Fix It!)

Problem

Your system crashes after:

Welcome to the Proxmox VE Installer
Loading drivers: .......

Cause

The efifb, vesafb, or simplefb drivers can grab your GPU before VFIO ever has a chance — and on single-GPU systems, this causes a lock-up.

✅ Solution: Use Temporary Boot Parameters

At the Proxmox ISO GRUB screen:

1. Highlight: Install Proxmox VE (Graphical)
2. Press E to edit
3. Find the linux line and append the following:

intel_iommu=on iommu=pt video=efifb:off video=vesafb:off video=simplefb:off nomodeset

📝 Use amd_iommu=on instead of intel_iommu=on if you’re on AMD.

4. Press Ctrl + X or F10 to boot

You should now bypass the crash and enter the installer.

🔹 Phase 2 — Step-by-Step Install Walkthrough (Using Thor as Example)

System Example – Thor

🔧 Proxmox Install Process

1. Choose your preferred language (e.g., English)
2. Accept the license agreement
3. Select your storage drive for the OS, 500 GB NVMe in my case.
4. Optional: Choose ZFS (RAID1 if multiple disks, or Single Disk ZFS for snapshot support).
5. Set location (e.g., Europe/London) and time zone
6. Create a strong root password (save this securely!)
7. Enter your admin email for alerts
8. Choose the NIC (should be your fastest interface, for me its 2.5 GbE)
9. Set hostname
10. Use static IP (recommended)
11. Example: 192.168.1.10
12. Gateway: 192.168.1.1
13. DNS: 1.1.1.1, 8.8.8.8
14. Double check settings
15. Click Install — takes a few minutes
16. Reboot When Prompted
17. Remove the USB stick
18. System will reboot into Proxmox

🔹 Phase 3 — Lock In Passthrough After Install

1. Edit GRUB Configuration

nano /etc/default/grub

2. Replace the GRUB line with the 

full passthrough config:

Intel Example (RTX 3090):

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt rd.driver.pre=vfio-pci pcie_acs_override=downstream,multifunction"

AMD Example:

GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on iommu=pt rd.driver.pre=vfio-pci pcie_acs_override=downstream,multifunction"

3. Update GRUB and Initramfs

update-grub
update-initramfs -u -k all

4. Blacklist Nouveau

echo -e "blacklist nouveau\noptions nouveau modeset=0" > /etc/modprobe.d/blacklist-nouveau.conf
update-initramfs -u

5. Optional: Bind the GPU to VFIO

Find device IDs:

lspci -nn | grep -i nvidia

Then bind:

echo "options vfio-pci ids=10de:xxxx,10de:yyyy" > /etc/modprobe.d/vfio.conf

Load VFIO modules:

echo -e "vfio\nvfio_pci\nvfio_iommu_type1\nvfio_virqfd" > /etc/modules

Reboot the system:

reboot

✅ Summary Table

📘 Reference

Based on: 

GRUB Parameters for GPU Passthrough: A Comprehensive Guide

1. Introduction 1.1 Purpose and Scope GRUB parameters play a fundamental role in successful GPU passthrough, acting as the initial gatekeepers that prepare your system for this advanced virtualization technique. Think of these parameters as a set of specific instructions given to your computer at its earliest boot stage

theDev.ukJohn Jestin

Recovery From GRUB Configuration Issues in Proxmox

Even with careful planning, GRUB parameter changes can sometimes render your system unbootable. Let’s understand how to recover your system when this happens, just as we did when our framebuffer parameters caused issues.

theDev.ukJohn Jestin