I have an NAS attached to my router, using BTRFS as its filesystem. Long story short, the partition table got corrupted, including the BTRFS filesystem signature, and I'm trying to recover the filesystem definition if possible. One of the utilities to do this, btrfs-find-root, is not in the opkg distribution provided with OpenWRT. Am I missing something, or will I have to look outside the distro?
More advanced tasks like this are probably easier done on a full linux system, if you're indeed using a WRT1900ACS, you shouldn't have much of a problem to connect the disk (be it via USB, eSATA or plain SATA) to a normal desktop, running a full blown general purpose linux (and be it from live media).