It seems that with OZ 3.3.5 the magic number in the .ipk file has to set as debian package v. 2.0 If you have an older package (or one that shows up as a tar archive) the package manager (or ipkg on the command line) complains of and invalid magic number. I tried this with a few older packages (bluez from sourceforge) and some of the ones in the 3.3.5 feed and all I could tell that was different between them was the output from the \'file\' command. Any ideas?