After custom kernel build wlan is not working


I followed this :

but after install the wlan is not available. What can i do to get the wlan on RockPI 4b working?



Have you changed the rootfs, or just built the kernel?


only build the kernel. i want the CAN Bus feature in the Kernel. For IOT and automotive applications. A good solution is you enable this feature in the std kernel? Can you do this?



I think you are using some HAT such as SPI CAN, right? In this case, you can use the device tree overlay. Which HAT are you using? You should have the dtbo for the HAT and enable it in the /boot/hw_intfc.conf


yes i use SPI CAN und an IF via USB but both need the CAN Kernel feature ;o) SPI is not my problem.
and i can see “make menuconfig” CAN is not enabled.

CAN is a part of the network part in the kernel


Do you know which exactly the chip is? We can enable those kernel modules.


i use this 2 devices. if the Kernel CAN modul is enabled and for the pican is the devicetree configured then CAN is working. (I use this on raspberry pi and bbb or debian on my laptop) but without the CAN in the Kernel network stack, it dosent’t work ;o)


I also bought a PiCAN2 CAN bus board for the Raspberry and some other practical tools directly from SK Pang Electronics. Last year I ordered an Omzlo PiMaster HAT with several CANZEROs via Kickstarter, but SocketCAN has nothing to do with the used hardware and does not have to be used. For sure SocketCAN brings advantages, otherwise VW would not have developed it either.

SocketCAN Concept

As described in Motivation / Why Using the Socket API the main goal of SocketCAN is to provide a socket interface to user space applications which builds upon the Linux network layer. In contrast to the commonly known TCP/IP and ethernet networking, the CAN bus is a broadcast-only(!) medium that has no MAC-layer addressing like ethernet. The CAN-identifier (can_id) is used for arbitration on the CAN-bus. Therefore the CAN-IDs have to be chosen uniquely on the bus. When designing a CAN-ECU network the CAN-IDs are mapped to be sent by a specific ECU. For this reason a CAN-ID can be treated best as a kind of source address.


right it has nothing todo with the HW. My problem is not the HW it is the CAN (VW) support in the kernel is not enabled.
I must compile a costumized kernel to use CAN BUS and its better this feature is enabled in the default kernel from radax.


The custom kernel looks for firmware in a different place than the radxa supplied kernel. I had to make some symbolic links to have wlan working. Check the syslog output for clues. I remember that I had to create /system/etc directory and create a link from /lib/firmware to /system/etc/firmware. I also think that I had to copy some files from a subdirectory of /lib/firmware to the /lib/firmware itself, but I forgot which. Looking which file are mentioned in the log, it is probably one of those:



thx lucho

pls for future build of the std radxa kernel. enable the CAN in the kernel.