I guess I'm going to revive this thread from the dead.
I have a KH-930e. I was able to successfully create a container pattern, uploaded the pattern to an Ubuntu laptop, modify it, and send the pattern back to the machine. I stopped here for a bit and picked up a few weeks later, working from my Win7-64bit desktop, mostly reviewing the code and trying to figure out everything it's doing (I'm a software engineer). Ran into a couple of problems, which may stem from the fact that I don't use pip and needed to install Pillow. Somewhere in there I decided to run the memcheck and clear the memory (returns without an error). Anyway.
From here, I started running into the problem mentioned by jixipix and troma. That was last night; was not able to solve it. Tonight, I tried using img2track to load a pattern into my machine. Nothing happened. So I tried to go back to using Becky's method (from my Windows machine). Nothing. Tried Becky's method from my Ubuntu machine. Nothing.
By "nothing", I mean that I can enter 551 on the machine (or 552), STEP, 1, STEP, the lamps go off like they're supposed to, and then the KM never comes back. I get no indication from either img2track or PDDemulate of any communication happening. (I should note here that I failed to be a Real Engineer and didn't document exactly what I did last night, so I can't be sure I'm actually doing the same things tonight.)
I've been trying to join the KMInternals group
, but haven't been accepted yet.
If anyone has any idea(s) of what's going on, I'd definitely like to hear them, because I'm pretty close to just ditching the Brother's electronics in favor of the Knitic Project
 If you're creating the bitmaps with the GIMP, it doesn't use the proper header format. You're either going to need to use a different image editor (I opted for MSPaint - open, re-save, close fixed the header) or edit the header manually (I believe there are some scripts out there to help with that).
 Current versions of Pillow don't like "import Image" - you need "from PIL import Image" [reference]