8821cu-20210916/FAQ.md

6.0 KiB

FAQ

Question: Is WPA3 supported?

Answer: WPA3-SAE is supported. It works well on most modern Linux distros but not all. Generally the reason for WPA3 not working on Linux distros is that the distro has an old version of wpa_supplicant or Network Manager. Your options are to upgrade to a more modern distro (distros released after mid 2022) or compile and install new versions of wpa_supplicant and/or Network Manager.


Question: I bought two usb wifi adapters based on this chipset and am planning to use both in the same computer. How do I set that up?

Answer: Realtek drivers do not support more than one adapter with the same chipset in the same computer. You can have multiple Realtek based adapters in the same computer as long as the adapters are based on different chipsets.


Question: Why do you recommend Mediatek based adapters when you maintain this repo for a Realtek driver?

Answer: Many new and existing Linux users already have adapters based on Realtek chipsets. This repo is for Linux users to support their existing adapters but my STRONG recommendation is for Linux users to seek out USB WiFi solutions based on Mediatek chipsets:

https://github.com/morrownr/USB-WiFi


Question: Will you put volunteers to work?

Answer: Yes. Post a message in Issues or Discussions if interested.


Question: I am having problems with my adapter and I use Virtualbox?

Answer: This article may help.


Question: The driver installation script completed successfully and the driver is installed but does not seem to be working. What is wrong?

Answer: Turn secure boot off to see if that allows the driver to work. This driver is primarily tested on Debian based distros such as Ubuntu, Raspberry Pi OS and Kali. In an attempt to make this driver work well on many Linux distros, other distros, including the Arch based Manjaro is used for testing. Currently I do not have installations of Fedora or OpenSUSE available for testing and reply on user reports of success or failure. I have two test systems with secure boot on so as to test secure boot. I have not seen any secure boot problems with Debian based systems and I don't remember problems with Manjaro.

dkms is used in the installation script. It helps with a lot of issues that will come up if a simple manual installation is used. dkms has the capability to handle the needs of secure boot. dkms was written by and is maintained by Dell. Dell has been offering some Ubuntu pre-loaded systems for years so their devs likely test on Ubuntu. I suspect Fedora and OpenSUSE may be handing their secure boot support differently than Debian based systems and this is leading to problems. This and the other repos I have are VERY heavily used and I am sure there are plenty of non-Debian users that use this driver. Are they all turning off secure boot and not reporting the problem? I don't know. What I do know is that reports like this are rare.

For the driver to compile and install correctly but not be available tells me there is likely a key issue. Here is an interesting link regarding Debian systems and secure boot:

https://wiki.debian.org/SecureBoot

That document contains a lot of information that can help an investigation into what the real problem is and I invite you and other Fedora, OpemSUSE and users of other distros that show this problem to investigate and present what you know to the devs of your distro via their problem reporting system. Turning off secure boot is NOT a fix. A real fix needs to happen.


Question: Can you provide additional information about monitor mode?

Answer: I have a repo that is setup to help with monitor mode:

https://github.com/morrownr/Monitor_Mode

Work to improve monitor mode is ongoing with this driver. Your reports of success or failure are needed. If you have yet to buy an adapter to use with monitor mode, there are adapters available that are known to work very well with monitor mode. My recommendation for those looking to buy an adapter for monitor mode is to buy adapters based on the following chipsets: mt7921au, mt7612u, mt7610u, rtl8812au, rtl8821cu and rtl8811au. My specific recommendations for adapters in order of preference are:

ALFA AWUS036ACHM - long range - in-kernel driver

ALFA AWUS036ACM - in-kernel driver

ALFA AWUS036ACH - long range - driver

ALFA AWUS036ACS - driver

To ask questions, go to USB-WiFi and post in Discussions or Issues.


Question: I have an adapter with the 8821cu chipset and it supports bluetooth. The bluetooth works but the wifi does not. What is wrong?

Answer: There appears to be an issue where adapters can be set up differently by makers. The fix is to set the driver option ( rtw_RFE_type ) in 8821cu.conf. The easiest way to edit 8821cu.conf is to run the following from the driver directory:

sudo ./edit-options.sh

Once in the document, you can scroll down to the documentation about rtw_RFE_type. You will likely have to experiment to find out what setting works best for your adapter but a good place to start is probably...

rtw_RFE_type=7

Simply add that option to the end of the options line, save and reboot.


Question: How do I disable the onboard WiFi in a Raspberry Pi?

Note: This answer is for the Raspberry Pi OS.

Answer:

Add the following line to /boot/config.txt

dtoverlay=disable-wifi

Question: How do I forget a saved WiFi network on a Raspberry Pi?

Note: This answer is for the Raspberry Pi OS without Network Manager active.

Step 1: Edit wpa_supplicant.conf

sudo ${EDITOR} /etc/wpa_supplicant/wpa_supplicant.conf

Note: Replace ${EDITOR} with the name of the text editor you wish to use.

Step 2: Delete the relevant WiFi network block (including the 'network=' and opening/closing braces).

Step 3: Save the file.

Step 4: Reboot