# Usin RFU and clRFU **URL:** \ **Category:** Rabbit\ **Created:** [July 25, 2011, 4:40pm UTC](https://forums.digi.com/t/usin-rfu-and-clrfu/10985 "2011-07-25T16:40:02Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![SeeCwriter](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@SeeCwriter](https://forums.digi.com/u/SeeCwriter)\ **Post date:** [July 25, 2011, 4:40pm UTC](https://forums.digi.com/t/usin-rfu-and-clrfu/10985/1 "2011-07-25T16:40:02Z")
I’m using DC 10.66 with an RCM6700, and RFU v4.62, that comes with DC. Both the RFU and clRFU works fine as long as DC is installed on the PC. If I take either the RFU or clRFU to a PC that does not have DC installed, I am unable to program the RCM6700. I have copied the entire contents of DCRABBIT\_10.66\Utilities to the PC and all the \*.bin files in DCRABBIT\_10.66\Bios to the PC, and put them all in the same directory along with my application bin file. The RFU gives error message: “failed to load image” The clRFU doesn’t give an error message. But the screen printout is as follows: \>Sending Coldloader \>363 of 254129 bytes sent \>Sending Pilot BIOS \>3887 of 254129 bytes sent \>Elapsed Time: 9.578 seconds \> The clRFU never downloads my bin file. The clRFU commandline is: clrfu myapp.bin -s 1:115200 -cl .\coldload.bin -pb .\pilot.bin -v -vp- Anyone know the secret to get the clRFU working on a PC that doesn’t have Dynamic C installed on it? I am not using a USB port on the PC, just straight serial. I am not using a USB adapter. And I have the “Use USB to serial converter” option on the RFU unchecked. FYI, I’ve been using the RFU and clRFU for Dynamic C v7.xx,8.xx, and 9.xx for years successfully. Using the very same process as above. So I am not a novice at this. Something is different with this new stuff. And I can’t find any documentation on the Digi website about this, which is not unusual. It is the worst website for getting information I’ve had the misfortune to use. Steve