If btrfs is compiled as a kernel module, then you need to create an initramfs to load the module at boot. On Raspian (and other debian derivatives), update-initramfs
is the easiest method to do this.
If initramfs-tools
is installed, then any time apt-get
installs a new kernel, it should trigger update-initramfs
automatically.
sudo apt-get update
sudo apt-get install initramfs-tools
However, if you use rpi-update
to install a new kernel, then you'll need to run update-initramfs
manually before rebooting into the new kernel:
sudo update-initramfs -u -k <kernel-version>
This will create or update the initramfs in /boot/initrd.img-<kernel-version>
.
The final step is to add it to your boot config: add the following line to /boot/config.txt
:
initramfs initrd.img-<kernel-version> followkernel
initrd-<kernel-version>
must match exactly the name of the file in /boot
.
You'll need to repeat these steps every time you run rpi-update
.