You could use a boot floppy. Tom's rtb, or one of the several hundred other boot linux floppies could work for this too. You could also look at network or USB boot if your motherboard supports it, but I doubt it if you only have single connector cables
You could also take the time to install a tiny distro into another partition, boot from it, and then do your work with the umounted devices.
Several very viable options, but really the best is to just grab a 2 connector cable for 5 bucks (USD, not sure what the conversion or cost is to the Euro currently