How to add files or directories into bbl.bin

[xubaqian]

Linux has run on my zc707 successfully, and I want to add files or directories in some subdirectories, such as /root.

When I modified the initramfs.txt in conf subdirectory, the bbl.bin got bigger. But I couldn't see my file in linux.

When I modified the initramfs.txt in linux/arch/riscv subdirectory and added its path through make linux-menuconfig, the bbl.bin remains invariant.

I don't know why.

I tried to modified buildroot, but don't konw how to do it.

Thanks for your help.

[jim-wilson]

Buildroot is used to build the target filesystem, so you will have to spend some time looking at that. There are multiple ways to modify it. Using BR2_ROOTFS_OVERLAY="" looks like one of the easier approaches. Add it to config/buildroot-initramfs_config or conf/buildroot_roorfs_config depending on which configuration you are using, or add it to both if you aren't sure.

See for instance https://buildroot.uclibc.org/downloads/manual/manual.html#rootfs-custom You should probably read other parts of the manual also.

I'm not a buildroot expert, and I've never done this myself, so I can't add any specific info.

[xubaqian]

I didn't see config/buildroot-initramfs_config or conf/buildroot_roorfs_config but modified the line BR2_ROOTFS_OVERLAY="/home/xqz/mybin" in work/buildroot/.config

cd work/buildroot
make
cd ../..
make

then the bbl.bin got bigger and in the work/sysroot I can see the files I added

However, on zc707, it stopped after the logo appeared.

                SIFIVE, INC.

         5555555555555555555555555
        5555                   5555
       5555                     5555
      5555                       5555
     5555       5555555555555555555555
    5555       555555555555555555555555
   5555                             5555
  5555                               5555
 5555                                 5555
5555555555555555555555555555          55555
 55555           555555555           55555
   55555           55555           55555
     55555           5           555555
       55555                   55555
         55555               55555
           55555           55555
             55555       55555
               55555   55555
                 555555555
                   55555
                     5

           SiFive RISC-V Coreplex

[terpstra]

If you are using sdboot, beware that it only downloads 16MiB. If your image exceeds that limit, it won't boot.

[xubaqian]

Success ! But can we raise its download limit ？

[jim-wilson]

sdboot seems to be a reference to a Xilinx board feature, so I don't know anything about that.

However, if you are booting from sdcard, then you probably have two partitions on your sdcard, and you should be able to put a linux filesystem on the second partition and mount it. You can then easily add as many files as you want to this linux filesystem. You could also put a linux disk image on it and chroot into it.

[terpstra]

@jim-wilson is mistaken. He's thinking of the system we are using internally for the HiFive/Unleashed board and have not yet ported to the freedom repository.