Sorry for my lack of reply. This forum makes it hard to follow threads you've replied to...
(unless you want to be bombarded with notification mails)
Here's what you end up with when you remove the image from your sample.pdf. It's a blank page. But you can still select and copy text out of it. I haven't tested it on the eReader, but with some luck the text will show up when you use Reflow.
The original PDF is really just an image (2079x2840 px) with a text layer on top that uses an "invisible font". Not sure if it would be possible to make the font visible to get somewhat of an image in the original layout back - the result would not look good though.
What could be done is a resized image, since the current one is too large for eReaders. I attached that too. Of course the quality is horrible.
Resizing was done with GhostScript; removal of the image with qpdf (convert pdf to qdf) and vim. I'm sure there are better tools... but is this result useful at all?
If the goal is reflow you could just as well convert it to txt in the first place, as that's really all there is once you remove the image.