Configuration files, such as upgrade script and setting files, are copied to the phone configuration banks in NVRAM, while phone images are stored in RAM
Note:
Image files are cleared if you reset the gateway.
Phone image banks are stored in the same TFTP directory. Therefore, you cannot copy the same file name to more then one bank. Copying a file to a bank containing a file with the same file name causes the old file to be overwritten by the new one.
File names for IP phone image files and script files are limited to 32 characters