How to use overlay for /lib/firmware ?

[fserb]

I know that since 6.9.1 there's a overlayfs on /lib/firmware and /lib/modules to "make it possible to install 3rd party modules at boot time"

 

I need to add some bluetooth driver file to /lib/firmware to be installed during boot.

 

The overlayfs allows me to write on /lib/firmware (that ends up on /var/local/overlay/lib/firmware) but the files I add there disappear after a reboot (obviously). I don't understand how I'm supposed to use it to install 3rd party modules (or in my case a patch) at boot time.

 

I understand how I could is this for modprobe, is this the only use case supported?

 

Do I need to regenerate bzfirmware? If so, is there a tutorial for that?

 

My actual problem:

[   16.149827] Bluetooth: hci0: BCM: firmware Patch file not found, tried:
[   16.150209] Bluetooth: hci0: BCM: 'brcm/BCM20702A1-0a5c-21e8.hcd'

 

I have the hcd file, but not sure how to have it available at that point.

 

Thanks for the help.

 

[SimonF]

8 minutes ago, fserb said:

I don't understand how I'm supposed to use it to install 3rd party modules (or in my case a patch) at boot time

save them on the boot drive and in the go file cp to /lib/xxxxx

 

allso chmod permisions after cp.

 

 

Edited September 10, 2021 by SimonF

[fserb]

That doesn't seem to work. The go file gets executed way after the bluetooth module gets loaded.

 

What I end up doing is: on go file I copy the patch and rmmod/modprobe all BT modules. That seems to work fine.

 

[SimonF]

That is the only way to do it as far as I can see. Even with a plugin it will execute after kernel module is loaded so would need to be removed and reloaded within a plugin

[Squid]

https://wiki.unraid.net/Manual/Release_Notes/Unraid_OS_6.9.0#Better_Module.2FThird_Party_Driver_Support