mark, i have been working with these printers since seiko launched them, so trust me when i say you can't, so no guess work here!!
seiko initially didn't put the firmware on the website, as they thought it was something that a customer should not be doing. but for the last year or so you can download the 64s or ip-6600 firmware within the downloads sections. remember this is always the latest version and not the entire compilation since it's inception.