The image contains the Kobo firmware. At least part of that will be licensed. Parts of it is under one of the open source licences. As such, it shouldn't be made generally available. But, I consider making it available to people with the devices not a bad thing. If Kobo say something about it, that might change.
As to the problem, have you tried a factory reset using the buttons? See
https://www.mobileread.com/forums/showthread.php?p=2842901 for instructions. In case that doesn't work, I have sent you a PM with the link.