According to the release notes, the following fixes have been implemented:
- Fixed issue where pressing F2 to access BIOS does not work when connected to certain 4K monitor.
- Updated Integrated Graphics
- Fixed issue where Intel wireless adapters lose connectivity.
- Fixed issue where systems restarts instead of shutting down with Linux.
Download the update from Intel Download Center.
In general it seems that the list of fixes per BIOS release is getting shorter and shorter for the Haswell NUCs. Mine has been working very well, but there a number of users who have complained of various strange issues. Maybe we can interpret this as a sign of improved stability of the i3 and i5 NUCs. At least several users have confirmed that the restart after shutting down in Linux issue is now fixed.