Hi @casm,
Not sure what system you are on but you can give a very explicit path to the bin file in your dfu command
For example I have my bin files at c:\photon\system
so the dfu command to reflash system-part1-0.4.2-photon.bin and system-part2-0.4.2-photon.bin would be
dfu-util -d 0x2B04:0xD006 -a 0 -s 0x8020000 -D c:\photon\system\system-part1-0.4.2-photon.bin
dfu-util -d 0x2B04:0xD006 -a 0 -s 0x8060000:leave -D c:\photon\system\system-part2-0.4.2-photon.bin