How can I mount filesystems with > 4KB block sizes?

Woohoo, I solved it :)

The short answer is you can't mount >4k block size devices on x86 linux machines as far as I can tell without some serious kernel hacking.

However, there is a work around.. using fuse-ext2 to mount the disk:

fuseext2 -o ro -o sync_read /dev/sdb4 /mnt/

(you'll probably need to apt-get fuseext2 first..)

works perfectly first time!

This is basically going to be how people can recover their MyBook Live disks.

Howto blog post here: http://john-hunt.com/2013/04/25/recovering-data-from-a-wd-mybook-live-2tb-3tbor-similar/