The Nook ereader can display Irish correctly, with its accent marks correctly displayed, but there is a problem with the new software. In the list of titles in the Library, it no longer handles accent marks.
For instance I have an Irish translation of The Adventures of Alice in Wonderland. The title used to be displayed as "Eachtraí Eilíse i dTír na nIontas" which is correct. After the "improvement was downloaded, the title is now displayed as "EachtraÃ± EilÃ±se i dTÃ-r na nIontas".
I hope this is an oversight and can be straightened out soon.