Originally Posted by veole
What's the problem with using Calibre to convert from mobi to eupub, edit the epub file, and then to use Calibre to convert it again to mobi?
Why is better to decompile the mobi file and edit raw html?
If you're using the epub and mobi for yourself, no reason. If you're planning to sell it, Amazon has rejected a lot of files made with Calibre, over the last few years, starting in 2010, and on-and-off through now. Now, mostly off, and even books made with Scrivener are occasionally being rejected. So, the answer is: it depends. ;-)
With regard to the ePUB, I prefer to make my own, over Calibre's coding. A lot.