I believe the Elonex 511EB is a re-badged Hanvon N520. See this blog post:
http://shkspr.mobi/blog/index.php/20...rmware-update/ and this item in the wiki:
https://wiki.mobileread.com/wiki/WISEreader_N520
And you're right — there doesn't seem to be a specific form for it. How odd.