Hi:
I'm not doing a big quoted reply, because we're getting lengthy. I'm sure I'll regret it as I decide I just GOTTA quote x, y and z, before I"m done.
A couple of semi-random notes:
- I know that {font-name here redacted per OP request] has an actual bold face. You might get better results by simply using that, instead of faux-weighting the regular font.
- Not to go off the reservation here, but...my recollection is that {ditto on font name redaction) doesn't *have* an eBook or app licensing option. Now, these are your books, not mine, but I spend all day dealing with OPIP (other people's IP), and I just want to be sure that you are not running into any possible problems by embedding a font that you MAY NOT have licensed.
- I think I have a similar font, somewhere, that's OS, if you need one. FWIW.
- The Voyage uses KF8.
- I can confirm that there is a process, called the PW (Publishing Workflow) that occurs after a file, of whatever origin, is uploaded at Amazon. Now, this happens AFTER the Step-6 mobi is created. During the PW process, the SRL (Start Reading Location) is set, and other things can happen. Mostly, the SRL is what gets altered, but now it sounds like something else is occurring. What's weird is that it's only for the Fire 6"--or, actually, am I right in saying, you THINK it's only for the Fire 6", because you have nothing else upon which to test, is that right?
- More stupid questions: how long have you had the 6", and do you regularly use it for reading OP's books? You've downloaded and read/tested/viewed the original mobi files, that you made in 2010-11, right? I know you said, Word-->Filt. HTML-->whatever in here-->Sigil-->Command line Kindlegen, is that right? Just confirming.
- Do you know/remember if those were KF6-7 files? Rather than KF8? Did they also have fonts, at that time, for the chapter head?
- When you built those files, what devices did you test them on, then? And again, in case I didn't ask, you built those books with the same chapter head font, and confirmed that it was working?
Given that your four books are all having the same issue, and presumably, they weren't all created at the same time, nor in precisely the same way, I'd guess that Amazon has a bug, just as they do with the Voyage (on images). Amazon has a number of weirdo issues related to fonts and font embedding. I would ask,
have you tried a version that has NO fonts embedded? For the Chapter head? Call something else, one of the sans-serifs, maybe Trebuchet, say? (For a true bracket navigation test, start with NO fonts, and work up to even trying to call something from the firmware/software). Remove the fonts folder from the file altogether, and see if that has an impact?
And for those who think that idea is a bit nutty--I've seen books that would have the font folder entirely ripped out, if a mobi was uploaded, not build with fonts if an ePUB was uploaded, but worked perfectly FINE if you break the ePUB into its constituent parts, zip it, and then upload THAT. Same exact content--just in a different wrapper. So...trying the whacky is almost a necessity.
I tend to think that I'm off the rails here--that the hyphenation issue is utterly unrelated to fonts, but the font WEIGHT issue mayn't be. I think I've mentioned here on MR before that I've seen things affected, by the simple inclusion of a font, that, in no common-sense way, should have been (affected). I've posted screenshots of the myriad font weirdnesses we've had, so...it will be interesting to see what Amazon says. ($5 says, the first thing they say is, remove fonts. Just because that's kind of their "go-to" on weirdness issues. That, or you never hear from them again.)