how can I upload a hex file to an arduino uno? I have a Rostock Max 3d with an Arduino Uno as the controller. The OEM has a firmware version I would like to upload, but it is in the hex file format. 

I have looked all over the Arduino IDE, but did not found a way to upload a hex file to the Arduino. I tried using AVRDUDE, but the Arduino only communicates with my PC when I set the "Programmer" to AVRISP. I have uploaded other codes for blink, and hello_world, but haven't been able to compile the firmware source. I was hoping I could just use the hexfile included in the firmware package. 

My OS is Linux.
I use a standalone programmer that uploads a .hex file from an SD card via the ICSP interface.