Not sure how many views this forum gets nowadays, but here goes ...

Does an Xprotolab Plain of 2014 vintage support DFU?

I tried grounding pin PC3 (the default DFU sensing pin for the ATXMEGA32A4U) and pin PA4 (the K1 pin on other Xprotolab devices) while powering up, both to no avail.

Is it simply the case that Xprotolab Plain devices were never flashed with the DFU boot loader during manufacture? If so, can anyone recommend a cheap AVR ISP device that supports PDI mode?