According to https://bugzilla.opensuse.org/show_bug.cgi?id=897855#c7 it seems sane-backends development version git20150108 may not yet have the actual root cause fixed. Because both in bug#897855 and also here there is "Error during device I/O" I think the root cause is basically the same and I still think the actual root cause is some lover level USB stuff (see also bug#897855). Regardless that you disagree with my reasoning in bug#903839 that I cannot do anything unless I can reprodue your issue on my system, I still think you should really report your issue directly to the sane-backends authors at the SANE project http://www.sane-project.org so that there is a direct communication between you and the upstream authors. It would be best when you report it on the sane-devel mailing list so that the upstream authors plus other interested users can notice the issue, see http://www.sane-project.org/mailing-lists.html