I just installed Armbian_community_26.2.0-trunk.732_Rockpi-4bplus_trixie_current_6.18.22_minimal on a Rockpi-4bplus.

How do I install the correct Linux headers? The standard apt install linux-headers-$(uname -r) method doesn't work for armbian.
OK, there's a corresponding option in armbian-config, and it seems to run successfully, but for some reason, I only see linux-headers-6.12.74+deb13+1-arm64 and linux-headers-6.12.74+deb13+1-common in /usr/src.

We don't ship headers for each and every trunk image. Way too much data. 

Simplest solution is to use the framework to create a complete set of kernel deb packages. Those will include matching headers.

Thanks, @Werner! I believe I can do it once I find clear instructions. There's still a lot I don't understand—where all needed things are. I'd appreciate it if you could just provide a link that could point me in the right direction.

Meanwhile, yesterday I somehow managed to install the headers using apt-get install linux-headers-current-rockchip64 . At least, for now, this allowed me to build the packages that needed the headers.

It seems like this might be a bit of a dirty trick (no?). So, I'd still like to do it right.

Okay so then we have some issues here

19 hours ago, Stanislav Chizhik said:

armbian-config, and it seems to run successfully, but for some reason, I only see linux-headers-6.12.74+deb13+1-arm64 and linux-headers-6.12.74+deb13+1-common in /usr/src

This is clearly wrong since these packages come from upstream Debian and cannot/will not work with Armbian kernels. This shall be reported here: https://github.com/armbian/configng/

 

1 hour ago, Stanislav Chizhik said:

sing apt-get install linux-headers-current-rockchip64

Then you were lucky some working headers were present

 

1 hour ago, Stanislav Chizhik said:

a link that could point me in the right direction

 

https://docs.armbian.com/Developer-Guide_Build-Preparation/

 

Or in very short:

git clone the repo

./compile.sh BOARD=rockpi-4bplus BRANCH=current kernel

Check output/debs for your packages

Install via dpkg -i on the target board

Community images are tied to daily beta repo where it should always be a match kernel - headers. Just make sure you have a clean updated system then proceeding to header installation via armbian-config. And only if this doesn't work, report so we can look into.

One thing that helped me in a similar situation was checking that the running kernel version matched the headers exactly with uname -r. A mismatch there can be really confusing. If you've recently upgraded the kernel, a reboot before installing the headers is worth trying too.