Wireless USB Adapter 0bda:c811 Realtek Semiconductor Corp
The good news is that your 0bda:c811 device has support and has been the subject of several answers and duplicates here before; for example: USB WIFI Realtek not an MTP device The bad news is that the previous driver files will not properly compile on Ubuntu 19.04 using a 5.0.0-xx kernel version.
I recommend that you use another method. With a temporary working internet connection, open a terminal and do:
sudo apt update
sudo apt install build-essential git dkms bc
git clone https://github.com/brektrou/rtl8821CU.git
cd rtl8821CU
chmod +x dkms-install.sh
sudo ./dkms-install.sh
It builds successfully, albeit with a few possibly harmless warnings, on my 5.0.0-23 system
Next, do:
sudo modprobe 8821cu
Your wireless should now be working.
KTO
Updated on September 18, 2022Comments
-
KTO over 1 year
I am a bit lost sorting through the pile of documentation and Q&As about this topic so im just going to specifically ask.
I run an ASUS laptop, its a few years old and is unable to use 5ghz wifi, so i have use a usb wireless adapter (Flenco is the brand name, its just a standard 600mbps adapter, and no im not sure what serious of words and numbers anyone would need to identify it lol), to connect to the much faster wifi. on windows obviously no issue, plug and play etc. its the difference between 4-6 mbps download and 45-60mbps download.
I can not for the life of me get my linux to see it, and im too much of a noob to keep randomly messing up my system grasping at straws. It doesnt show up when i run lsusb, at least not under any name that would lead me down a fix path, not that i would know what to do from there anyways.
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 004: ID 04ca:2006 Lite-On Technology Corp. Broadcom BCM43142A0 Bluetooth Device Bus 001 Device 003: ID 04f2:b483 Chicony Electronics Co., Ltd Bus 001 Device 008: ID 05a7:1020 Bose Corp. Bus 001 Device 007: ID 04d9:a0f0 Holtek Semiconductor, Inc. Bus 001 Device 006: ID 1a40:0101 Terminus Technology Inc. Hub Bus 001 Device 002: ID 0bda:c811 Realtek Semiconductor Corp. Bus 001 Device 005: ID 0c45:5004 Microdia Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
I am completely positive this has been solved a hundred times over and I apologize for that, if someone could maybe point me towards a prior answer or offer a little more direct guidance that would be amazing.
I run Ubuntu 19.04, everything is up to date and working very well, just this issue.
Thanks!
Bus 001 Device 009: ID 0bda:c811 Realtek Semiconductor Corp. Couldn't open device, some information will be missing Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x0bda Realtek Semiconductor Corp. idProduct 0xc811 bcdDevice 2.00 iManufacturer 1 iProduct 2 iSerial 3 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0035 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xa0 (Bus Powered) Remote Wakeup MaxPower 500mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 5 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 255 Vendor Specific Subclass bInterfaceProtocol 255 Vendor Specific Protocol iInterface 2 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x84 EP 4 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x05 EP 5 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x06 EP 6 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x87 EP 7 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 3 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x08 EP 8 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0
this is the only entry that changed.
also, model number is X455L.
-
mikewhatever almost 5 yearsLooks like 0bda:c811 is the device, and it's unsupported.
-
K7AAY almost 5 yearsLooks like X455L is an incomplete model name; should have an extra letter or two after the L. You could have a X455LA, X455LAB, X455LB, X455LD, X455LDB, X455LF, X455LJ, X455LN, or X455LNB. Can you try asus.com/us/support/Article/565 ?
-
K7AAY almost 5 yearsDiscussion of WiFi card change at forums.tomshardware.com/threads/… and asus.com/US/support/FAQ/1037422
-
chili555 almost 5 years@mikewhatever askubuntu.com/questions/1089790/… and see my answer below.
-
mikewhatever almost 5 years@chili555 Glad you are on it. I don't have the device, but if it works, well, better later then never.
-
Admin about 2 yearsthat's my wifi dongle, thanks for ansking!
-
-
bmaupin about 4 yearsThis worked great! Because I was working from a new install and didn't have an existing network connection, I was able to install dkms from the USB install media using the instructions here: askubuntu.com/a/1173564/18665
-
Jim C about 4 yearsPerfect, this worked 100% well on Ubuntu 18.04 LTS for me too. Thanks a ton! :-)
-
Codebling about 4 yearsFails without
bc
, adding it toapt install
command -
chili555 about 4 years
bc
is installed as a part ofbuild-essential
and its dependencieslibc6
andlibc6-dev
. It needn't be specified explicitly. -
apos almost 4 yearsWorks great with Cudy AC 650 wireless USB stick (lsusb -> ID 0bda:c811 Realtek Semiconductor Corp. 802.11ac NIC). Ubuntu 20.04, Kernel 5.4. No problems at all. Follow the advice above and add "8821cu" to /etc/modules, so it will be loaded on the next boot.
-
Roger Vadim over 3 yearsDidn't work for me unfortunately (same adapter, but HP Compaq):
modprobe: FATAL: Module 8821cu not found.
-
chili555 over 3 years@Vadim Please start your own new question and show the terminal output of the
sudo ./dkms-install.sh
command. I suspect that it does not complete correctly. -
Jorge Arévalo over 3 yearsThanks! That made my day
-
u2n about 3 yearsFor any who find this thread in a frustrating search for the fabled preexistng driver referenced elsewhere, ya just forget that; it doesn't exist. This is the best, easiest way to make the device work. Don't waste hours struggling, just do like this answer says and life will get a lot better.
-
AliF50 almost 3 yearsThanks so much @chili555, I tried so many variations of other stuff on the internet but this method made it work instantaneously.
-
Jeff Ward over 2 yearsWorked on 20.04.3 kernel 5.11.0-37-generic - thanks!
-
Teo7 over 2 yearsAs a few comments above, I too was unable to complete the installation because the bc package was missing, evidently not installed with build-essential.
-
chili555 over 2 yearsbc is evidently no longer a dependency of build-essential. I've amended my answer accordingly.
-
johndpope about 2 yearsBOOM - working. thx
-
twowheeler about 2 yearsJust confirming that this still works with kernel 5.16.15, impish amd64.
-
Ki Ko about 2 yearsgreat help. thank a lot. worked on ubuntu 20.04 kernel 5.13.0-39-generic
-
Admin almost 2 yearsAs I reported in github there is an issue with kernel 5.17.9 . is there any update ?