Public bug reported:
SUMMARY
iwlwifi (Intel Wi-Fi 6E AX211) firmware crashes repeatedly with
"Microcode SW error detected. Restarting 0x0." on kernel 7.0
(Ubuntu 26.04 LTS). Regression: the same hardware was fully stable
on Ubuntu 25.10 (kernel 6.17). The crash makes the machine unusable
within minutes of normal use, and is reliably triggered by network
activity (e.g. fetching mail in Thunderbird).
HARDWARE
- Laptop: Lenovo Yoga Slim 6 14IAP8 (machine type 82WU)
- CPU: Intel Alder Lake (12th gen, hybrid)
- Wi-Fi: Intel Wi-Fi 6E AX211 160MHz (PCI 0000:00:14.3)
- Detected crf-id 0x400410, cnv-id 0x80400
- BIOS: Lenovo KTCN39WW (2023-08-18)
SOFTWARE
- Ubuntu 26.04 LTS (upgraded from 25.10)
- Affected kernels: 7.0.0-22-generic AND 7.0.0-15-generic
(both crash identically)
- Wi-Fi firmware: 89.123cf747.0 so-a0-gf-a0-89.ucode (op_mode iwlmvm)
- linux-firmware: 20260319.git217ca6e4.1ubuntu (latest available)
CRASH SIGNATURE
iwlwifi 0000:00:14.3: Microcode SW error detected. Restarting 0x0.
WARNING: drivers/net/wireless/intel/iwlwifi/iwl-trans.h:1097
at iwl_pcie_irq_handle_error+0x1ba/0x200 [iwlwifi]
iwlwifi 0000:00:14.3: Start IWL Error Log Dump:
iwlwifi 0000:00:14.3: 0x00000B03 | IML/ROM error/state
iwlwifi 0000:00:14.3: 0x60000000 | FSEQ_ERROR_CODE
Also observed just before the crash:
iwlwifi 0000:00:14.3: [0] Got MSI-X interrupt before we have Rx queues
REGRESSION DETAILS
- Ubuntu 25.10 with kernel 6.17.0-x: STABLE, no Wi-Fi crashes.
- After upgrade to Ubuntu 26.04 (kernel 7.0.0-x): crashes within
minutes, every session.
- Identical crash on both 7.0.0-15 and 7.0.0-22, so it is not
specific to a single 7.0 build.
WORKAROUNDS TESTED (none resolved the crash)
- intel_iommu=off : removed the accompanying DMAR/IOMMU faults from
the log, but the iwlwifi Microcode SW error still occurs.
- iommu=pt : same result (DMAR faults gone, Wi-Fi crash remains).
- modprobe options iwlwifi power_save=0 uapsd_disable=1 11n_disable=8 :
no effect on the crash.
- Booting the older installed kernel (7.0.0-15): same crash.
The DMAR/IOMMU faults therefore appear to be a side effect, not the
root cause. The root cause is the iwlwifi/firmware initialization
failure (IML/ROM error, FSEQ_ERROR_CODE) on the 7.0 kernel.
EXPECTED
Wi-Fi remains stable under normal use, as it did on kernel 6.17
(Ubuntu 25.10).
ACTUAL
Repeated iwlwifi microcode crashes, Wi-Fi drops and full system
instability within minutes.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-22-generic 7.0.0-22.22
ProcVersionSignature: Ubuntu 7.0.0-22.22-generic 7.0.0
Uname: Linux 7.0.0-22-generic x86_64
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: nicolas 5182 F.... pipewire
nicolas 5202 F.... wireplumber
/dev/snd/seq: nicolas 5182 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sat Jun 20 03:38:54 2026
InstallationDate: Installed on 2025-02-06 (498 days ago)
InstallationMedia: Ubuntu 24.10 "Oracular Oriole" - Release amd64 (20241009.4)
MachineType: LENOVO 82WU
ProcEnviron:
LANG=fr_FR.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-22-generic
root=UUID=3b9eac6f-0152-405e-9800-5d424a52c8ed ro quiet splash iommu=off
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-05-19 (32 days ago)
dmi.bios.date: 08/18/2023
dmi.bios.release: 1.39
dmi.bios.vendor: LENOVO
dmi.bios.version: KTCN39WW
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: LNVNB161216
dmi.board.vendor: LENOVO
dmi.board.version: SDK0T76463 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Yoga Slim 6 14IAP8
dmi.ec.firmware.release: 1.39
dmi.modalias:
dmi:bvnLENOVO:bvrKTCN39WW:bd08/18/2023:br1.39:efr1.39:svnLENOVO:pn82WU:pvrYogaSlim614IAP8:rvnLENOVO:rnLNVNB161216:rvrSDK0T76463WIN:cvnLENOVO:ct10:cvrYogaSlim614IAP8:skuLENOVO_MT_82WU_BU_idea_FM_YogaSlim614IAP8:pfaYogaSlim614IAP8:
dmi.product.family: Yoga Slim 6 14IAP8
dmi.product.name: 82WU
dmi.product.sku: LENOVO_MT_82WU_BU_idea_FM_Yoga Slim 6 14IAP8
dmi.product.version: Yoga Slim 6 14IAP8
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2157682
Title:
iwlwifi AX211 Microcode SW error on kernel 7.0 (regression from 6.17 /
Ubuntu 25.10)
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