Netgear recently updated the ReadyNAS firmware to RAIDiator 4.1.5. This version contains some fixes and updates but doesn’t change the base kernel version used. Thus, the iSCSI Target Support for ReadyNAS will continue to work unchanged.
However, some manual work has to be done to re-enable the automatic startup and shutdown of the iSCSI daemon after an upgrade to RAIDiator 4.1.5. Read about it here.