Flashing ATmega8U2 using another Arduino I have an Anduino Uno R1 and the ATmega8U2 on. It does not respond correctly. How can I use another Arduino Uno R3 in order to reinstall the correct firmware? What I want to avoid it to solder the resistor because I am not very good with the soldering iron.

As fas as I understand there are some pins close to the AREF pin that can be used in order to attach a programmer. Also how can I temporally attach them without the need of a soldering iron? On the R1 the pins are just some exposed metal. How can I connect to them?

Also, if I load into the other Arduino the programmer, then how can I load the firmware using GNU/Linux into the ATmega8U2?
There is an official guide. Arduino as ISP and Arduino Bootloaders

But you need to add the 2x3 ISP pin header since some of the signals isn't available on D0-D13 or any other pins.