Public bug reported:
linux-firmware-amd-graphics 20240318.git3b128b60-0ubuntu3.4 (noble-updates,
published 2026-11-04) breaks display output on RDNA4 / DCN 4.0.1 GPUs.
In the 0ubuntu3.4 .deb, the DCN 4.0.1 DMCUB firmware is a symlink to the
DCN 3.2.0 (RDNA3) firmware:
0ubuntu3.3:
-rw-r--r-- 225553 ./lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst
0ubuntu3.4:
lrwxrwxrwx 0 ./lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst ->
dcn_3_2_0_dmcub.bin.zst
(verified with `dpkg-deb -c` on both packages downloaded from Launchpad;
3.4 contains exactly one more symlink than 3.3)
amdgpu therefore loads the wrong DMCUB image, PSP rejects it, and there is no
display output (black screen after boot; only nomodeset works).
Hardware:
03:00.0 VGA [0300]: AMD Navi 48 [Radeon RX 9070/9070 XT/9070 GRE] [1002:7550]
(rev c0)
Subsystem: PowerColor Reaper RX 9070 XT [148c:2435]
Release: Ubuntu 24.04 (noble)
Reproduced with kernels: 7.0.0-42-generic (HWE) and 7.2.15 (xanmod).
Not kernel-dependent, as the firmware file itself is wrong.
dmesg with 0ubuntu3.4:
amdgpu 0000:03:00.0: [drm] Loading DMUB firmware via PSP: version=0x07002F00
amdgpu 0000:03:00.0: failed to load ucode DMCUB(0x3F)
amdgpu 0000:03:00.0: psp gfx command LOAD_IP_FW(0x6) failed and response
status is (0x11)
amdgpu 0000:03:00.0: [drm] Wait for DMUB auto-load failed: 3
amdgpu 0000:03:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB
error - collecting diagnostic data
dmesg with 0ubuntu3.3 (works):
amdgpu 0000:03:00.0: [drm] Loading DMUB firmware via PSP: version=0x0A000800
The 3.4 changelog (LP: #2168847) says "amdgpu: update dmcub fw for dcn32 and
dcn401". The dcn401 blob apparently ended up identical to the dcn32 one and
was then deduplicated into a symlink during packaging. (This is a guess based
on the symptoms; I have not checked the packaging scripts.)
Workaround:
Downgrade to 0ubuntu3.3 from Launchpad, `apt-mark hold
linux-firmware-amd-graphics`,
`update-initramfs -u -k all`.
Expected: dcn_4_0_1_dmcub.bin.zst should be the actual DCN 4.0.1 firmware
(upstream linux-firmware amdgpu/dcn_4_0_1_dmcub.bin, e.g. ucode version
0x0A005000
as of upstream commit 9ff0f3ab).
Since 3.4 is in -updates, all noble users with RX 9070-series cards
will get a black screen after updating.
** Affects: linux-firmware-amd-graphics (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2173163
Title:
[regression] 0ubuntu3.4 ships dcn_4_0_1_dmcub.bin.zst as symlink to
dcn_3_2_0 firmware – black screen on RX 9070 (Navi 48)
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