Then I have 2 questions: My original about where the CONTACTS_DIRECTORY can be overridden and, secondly, where is this blank phone specific contact file you refer to?
There is a 000000000000-directory.xml that has no items in it and is in /tftpboot/contacts.
However, If I manually code a 000xxxxxxxxx-directory.xml file for a phone AND place it in the /tftpboot folder, the Polycom SPIP 335 phone picks the directory up on reboot. However, the VVX 500 does not.
Looking at the directory structure, it appears the intention is that all contact files should go into the /tftpboot/contacts directory, but they appear to be ignored because of the above CONTACTS_DIRECTORY="" setting in the 000xxxxxxxxx.cfg file.