Hi Olle,
I have beed testing bita on a project I'm working on and it is a very promising tool.
Unfortunately, there are two features/improvements that are missing for my use case:

1. The dictionary creation is by far the slowest part of the cloning process for me. That part alone takes almost 3 minutes. The actual transmission is much faster then (5-10 seconds). If we could avoid this duplicate work, it would translate to multiple days of extra battery life on my project (assuming normal operation).
   While looking into this, I saw that you had already planned for a mechanism to tackle this at some point (see Implement chunk index cache #3).
   Could you tell me whether there was a specific reason to not implement this?

2. If the download fails due to a bad connection, I think it would be very helpful to be able to resume transmissions. My suggestion would be to save the dictionary of the downloaded chunks during cloning. So something like:

   $ bita clone \
     --seed /dev/mmcblk0p1 \
     --seed-dictionary /path/to/archive/of/dev/mmcblk0p1 \
     http://file.to.clone \
     <output path or stream> \
     --save-dictionary /path/for/cloned/dictionary
   

   Now if the download succeds, we can use the seed dictionary for a future clone. However, if it fails, we could continue the transmission by either having a clone resume option or the option to clone with multiple seeds. So something like:

   $ bita clone \
     --seed /dev/mmcblk0p1 \
     --seed-dictionary /path/to/archive/of/dev/mmcblk0p1 \
     --seed /path/to/faild/update/or/other/file/that/is/expected/to/share/data/with/server/file \
     --seed-dictionary /path/to/failed/dictionary \
     http://file.to.clone <output path or stream> \
     --save-dictionary /path/for/cloned/dictionary
   

   Of course both of these features would require the user to make sure that the seeds are not modified after dictionary creation.