How to get AX1650 working on Debian Linux?
As described by Intel, this particular wireless card needs some hacking, because Debian installer does not contain the necessary firmware:
https://www.intel.com/content/www/us/en/support/articles/000058910/wireless/intel-wireless-products.html
However, following their instructions did not solve the problem. I've tried this one too, without success: https://m7c1.com/posts/install-killer-ax1650-drivers-and-get-wifi-with-only-a-usb-and-a-debian-netinstaller
From the kernel log file it seems that something's fishy with the firmware version
[ 1.750300] iwlwifi 0000:00:14.3: Direct firmware load for iwl-dbg-cfg.ini failed with error -2
[ 1.750523] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-55.ucode (-2)
[ 1.750565] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-55.ucode failed with error -2
[ 1.750573] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-54.ucode (-2)
[ 1.750610] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-54.ucode failed with error -2
[ 1.750616] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-53.ucode (-2)
[ 1.750651] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-53.ucode failed with error -2
[ 1.750656] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-52.ucode (-2)
[ 1.750690] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-52.ucode failed with error -2
[ 1.750693] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-51.ucode (-2)
[ 1.750726] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-51.ucode failed with error -2
[ 1.750731] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-50.ucode (-2)
[ 1.750762] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-50.ucode failed with error -2
[ 1.750765] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-49.ucode (-2)
[ 1.750794] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-49.ucode failed with error -2
[ 1.751172] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-48.ucode (-2)
[ 1.751196] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-48.ucode failed with error -2
[ 1.751201] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-47.ucode (-2)
[ 1.751225] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-47.ucode failed with error -2
[ 1.751229] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-46.ucode (-2)
[ 1.751260] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-46.ucode failed with error -2
[ 1.751265] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-45.ucode (-2)
[ 1.751293] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-45.ucode failed with error -2
[ 1.751297] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-44.ucode (-2)
[ 1.751320] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-44.ucode failed with error -2
[ 1.751323] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-43.ucode (-2)
[ 1.751346] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-43.ucode failed with error -2
[ 1.751350] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-42.ucode (-2)
[ 1.751373] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-42.ucode failed with error -2
[ 1.751377] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-41.ucode (-2)
[ 1.751400] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-41.ucode failed with error -2
[ 1.751404] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-40.ucode (-2)
[ 1.751429] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-40.ucode failed with error -2
[ 1.751433] iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-Qu-b0-hr-b0-39.ucode (-2)
[ 1.751457] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-Qu-b0-hr-b0-39.ucode failed with error -2
[ 1.751458] iwlwifi 0000:00:14.3: no suitable firmware found!
[ 1.751482] iwlwifi 0000:00:14.3: minimum version required: iwlwifi-Qu-b0-hr-b0-39
[ 1.751508] iwlwifi 0000:00:14.3: maximum version supported: iwlwifi-Qu-b0-hr-b0-55
Any idea how to get this working? I have kernel version 4.19.0-17-amd64, but also tried upgrading to linux-image-amd64 (5.10.46-2~bpo10+1).
EDIT: SOLVED! I've upgraded kernel to 5.10.x and installed the iwlwifi firmware from bullseye_di_rc3/, and it works! Thank you so much for helping!
What I don't get is why don't they just include the latest kernel into the installer...
EDIT2: The connection is very unstable though. It oftentimes disconnects and fails to reconnect with error "Authentication request to the driver failed". I know it's not the AP's fault, I have other devices connected to the same network, they run flawlessly.
Your best bet here is to install the kernel and the firmware-iwlwifi package from bullseye. The kernel contains support for this chip, and the firmware appears to be properly packaged (although I don't have that chip, so I can't verify).
If you're trying to install for the first time, you can either install without the firmware from the buster or bullseye official images by using a wired connection and then install the appropriate packages, or you can try the unofficial bullseye images that support firmware, which should let you install using a Wi-Fi connection.