Marvin and Aldiko Can't Read ePub Metadata or Cover Page

On Windows 7, using the latest version of Calibre (64-bit), I have collected numerous public domain E-Books, made a few simple edits, and resaved them (using the "Convert Books" feature) in the ePub and mobi formats.

The edits included completing the Author and Title metadata fields and adding a Calibre-generated cover to each E-Book file.

I chose the No SVG Cover option during each conversion, because I was going to read some of the books on my iPhone. The Calibre Help Tips warned that with SVG, the iPhone would display the cover as a blank page.

I have successfully read these E-Books on the following applications:

• Kybook (iPhone)
• Moon+ Reader (Android tablet)
• Kindle Reader (iPhone, Android, and Windows)
• Calibre (Windows)
• SumatraPDF (Windows)
• Sigil (Windows)

Each of these above applications displays the cover page and the metadata created from within Calibre.

Recently, however, I tried two additional E-Book readers: Marvin (for the iPhone) and Aldiko (for Android tablet). Neither of these apps can read the E-Book metadata or display the cover page in my ePubs. I am wondering why this problem exists.

• Does the problem have something to do with the use or non-use of the SVG Wrapper on the cover page image? I really don't understand everything about SVG wrappers.
  
• Or, is it possible that Marvin and Aldiko are unable to search the E-Book to find the metadata? I noticed that in Calibre's Convert Books dialog box, under Structure Detection, there is an option to Insert Metadata as a Page at Start of Book. Is this feature necessary in order for some E-Book reader apps to work properly?

I'd appreciate your advice on how to resolve this problem.

Thanks.