Sometime ago I was given an interesting NAS device: D-Link DNS-323. Main problem with it lays in lack of support of cyrillic languages other than russian and share-based security model for SMB shares.
Device is Linux based but available GPL-ed source code lacks tools to build firmware image to flash device using its Web-interface.
There are some resources about customizing this device and adding a new functions (like Asterisk).
In next few posts I'll try to describe my progress in building customized firmware image to flash device using its web-interface (without losing ability to re-flash original firmware).