ATmega 32u4 bootloader without ISP connection

Hi,

is it possible to bootload an ATmega32u4 without having an ISP connection? So i.e. just use the USB connection?
I guess not but I couldn't find a definite answer searching the forums.

Thanks in advance.
BR Joerg

Depends on if the chip has the DFU (Direct Firmware Update) firmware installed.

so the next question would be if DFU is supported by the arduino IDE? Correct?

Or could i use a DFU-Programmer (http://dfu-programmer.sourceforge.net/) to burn the Arduino bootloader and use the IDE to upload my sketch afterwards?

Thanks for your help.

BR
Joerg

The IDE does not support DFU. You would typically use DFU to load the Arduino Leonardo firmware. Then you can use the Arduino bootloader to upload sketches.