Intel 5 GHz (802.11ac) wifi Failure After Kernel Update

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Intel Cannon Lake PCH CNVi Wi-Fi 5 GHz (802.11ac) Fails After System Update.

  • Operating System: Fedora Workstation (Version 43)
  • Wi-Fi Device: Intel Cannon Lake PCH CNVi WiFi ([8086:a370])
  • Driver in Use: iwlwifi
  • Interface Name: wlo1
  • Symptom: The 5 GHz network (802.11ac) is visible but fails to connect or drops immediately. The 2.4 GHz network works perfectly.
  • Key Observation: The 5 GHz network worked reliably when booted from the Live Installation ISO. The issue appeared only after installing Fedora to the hard drive and running system updates.

The kernel log (dmesg | grep iwl) consistently shows the following “Unhandled alg” error, which is often associated with authentication/encryption issues on the 5 GHz band:

iwlwifi 0000:00:14.3: Unhandled alg: 0x6c040707

The problematic firmware version loaded by the failing kernel is:

loaded firmware version 46.7e3e4b69.0 9000-pu-b0-jf-b0-46.ucode

I have attempted the following fixes, all of which failed to restore 5 GHz connectivity:

  1. Standard Codec/Firmware Reinstall: Reinstalling the linux-firmware package. (Verified internet connection was working during reinstall).
  2. Regulatory Domain Check: Confirmed the regulatory domain is correctly set to country IN: DFS-UNSET.
  3. Kernel Rollback: Manually rebooted and set the default kernel to the oldest version available on the system (6.17.1-300.fc43.x86_64). The issue persisted across all installed kernels.
  4. Driver Workaround (Software Crypto): Forced software encryption for the driver by adding options iwlwifi swcrypto=1 to /etc/modprobe.d/iwlwifi.conf.
  5. Driver Workaround (Firmware Rollback): Forced the driver to use a known stable firmware version by adding options iwlwifi fw_name=iwlwifi-9000-pu-b0-jf-b0-38.ucode to /etc/modprobe.d/iwlwifi-firmware.conf.
  6. NetworkManager Configuration: Deleted old connection profiles and attempted to create a new profile using nmcli with explicit security parameters (key-mgmt wpa-psk).
  7. Protocol Workaround (Disable 802.11ac): Disabled the 802.11ac protocol to force the use of 802.11n on the 5 GHz band by adding options iwlwifi 11ac_disable=1 to /etc/modprobe.d/iwlwifi.conf.

Any guidance or confirmation from other Intel CNVi users running the 6.17.x kernel series would be greatly appreciated.

2

I was able to find the solution. Wifi channel mode was set to auto in the router, change it to a ‘non_DFS’ channel from the router admin page and reconnect. This should connect to 802.11 ac wifi.