title_body: Is it possible to emulate the firmware of ereader devices?
upvoted_answer: It'd theoretically possible, but no device manufacturer (except for Amazon) bothered to develop and release emulators. 
  
  If you want to make sure that your epubs look OK on each device, you might want to check them with the desktop versions of Adobe Digital Editions, because all major eInk manufactures, except for Amazon, ship with an app that uses the same rendering engine. (All eInk device manufacturers that offer ADEPT DRM support are required to include RMDSK-based ePub apps, because no other ePub app will open ADEPT DRM-protected ebooks.)