If your router is already flashed with DD-WRT, the easiest way to get the drone working is to use SCP and MTD. Here's the quick 'n' dirty:
#SCP .trx file to router
scp filename.trx root@routerip:/tmp/
#SSH into router
ssh -lroot routerip
#Start the flash
cd /tmp
mtd -r write filename.trx linux
At this point the router will begin the flash process. Be patient, don't jump the gun and pull the plug on the router (potential brickage might follow). This usually takes 3-5 minutes, just wait for the router to reboot, then you will have to telnet back in and do the configure thing all over again.