Subject: RX 9070 (RDNA4) black screen / requires nomodeset on fresh install

Issues & Assistance
1

Hi,

I just did a fresh install of CachyOS Desktop on a new build:

  • CPU: AMD Ryzen 7 7800X3D

  • GPU: Gigabyte Radeon RX 9070 XT (Navi 48 - RDNA4)

  • Motherboard: Gigabyte B850 AORUS ELITE WIFI7

  • RAM: 64GB

  • Storage: Samsung 9100 PRO 2TB + WD Black SN7100 4TB

Problem:

  • The system only boots successfully if I add nomodeset kernel parameter.

  • Without nomodeset, I get a black screen / no signal.

  • Even with nomodeset, the GPU is not properly initialized (using llvmpipe software rendering).

  • I tried both the main kernel and LTS kernel. The issue is consistent.

  • I ran chwd -i amd and it says the profile is already installed.

What I’ve tried:

  • nomodeset

  • amdgpu.dc=0

  • Switching to LTS kernel

  • Reinstalling AMD packages

Is there a known issue with RDNA4 (Navi 48) cards on the current CachyOS kernels?
What is the recommended kernel parameter or driver setup for the RX 9070 series right now?

Thank you for any help.

2

hello, i’ve seen something similar in the past here : Unable to boot without nomodeset (amd gpu)

maybe ask them if they have found the issue ?