[hawkinsw]

Here are some of the steps that I use to unsquash the binary Commotion images to make changes:

1. Find the PARTs

2. Extract them

3. unsquash: unsquashfs -d image/ squashfs.bin

4. Make the changes.

5. squash: ~/code/commotion-openwrt/commotion-openwrt/openwrt/staging_dir/host/bin/mksquashfs4 image/ squashfs-made.bin -nopad -noappend -root-owned -comp xz -Xpreset 9 -Xe -Xlc 0 -Xlp 2 -Xpb 2 -b 256k

6. pad: ~/code/commotion-openwrt/commotion-openwrt/openwrt/staging_dir/host/bin/padjffs2 squashfs-made.bin 64

7. mkfwimage: ~/code/commotion-openwrt/commotion-openwrt/openwrt/staging_dir/host/bin/mkfwimage -B XM -k kernel.img -r squashfs-made.bin -v XM.ar7240.v6.0.0-OpenWrt-r36682 -o openwrt-ar71xx-generic-ubnt-nano-m-squashfs-factory-DR2-tn.bin

If you are modifying a sysugrade image: Extract 0-1048576 (bytes): that's the kernel Extract the rest: that's the squashfs

Put them back together with ( dd if=vmlinux bs=1048576 conv=sync; dd if=squashfs-made.bin ) > openwrt-ar71xx-generic-ubnt-bullet-m-squashfs-sysupgrade-DR2-custom.bin

These are just my notes. Feel free to contact me if you want more information.