There are swap settings to use when transferring files to a SD card or emmc which has an active swap running on it. Look in the swappolube threads if you find nothing I will try to watch this thread and try to post the specific swap settings I use for big file transfers.
BTW I prefer to use SCP(ftp over SSH tunnel) to move files to my devices over USB cable.
H-E-N was great but now the USB mode applet does it all automagically especially when using flash drives though it can also initiate other USB devices.