So im trying to bootload my friends cr10 and i dont have my arduino uno with me,its in the campus and no one can go in,but i have some arduino nanos here,is there a way for me to use it as a programer to bootload the firmware into the printer ? thanks
ps. some people suggested to use capacitors but i don't have any :C
Yes, you can use a Nano as an "Arduino as ISP" programmer just the same as an Uno:
If you're using the latest version of Arduino AVR Boards (you can check this at Tools > Board > Boards Manager), it's unlikely the capacitor will be necessary.
FYI, the correct term is "programmer", not "bootloader". The bootloader is the name for the firmware the programmer writes to the target microcontroller.
I always believed it necessary (although I've not done it for several years, since I got a USBasp). I thought that without that cap (on the Nano reset pin), when Upload using Programmer is clicked, the Nano would get programmed itself instead of acting as a programmer.
The only time I've ever found the reset disable capacitor necessary was when Arduino switched the Arduino as ISP programmer definition from using the stk500v1 protocol to the arduino protocol for a couple Arduino AVR Boards versions a while back:
Other than that, I've been using Arduino as ISP for years without ever a capacitor. I've never figured out what other factors influence whether it's needed. Even in Arduino's official tutorial, they use it on the Mega, but not on the Uno, even though I've never heard anything to indicate the Mega is more likely to need it than the Uno.
The 10µF electrolytic capacitor connected to RESET and GND of the programming board is needed only for the boards that have an interface between the microcontroller and the computer's USB, like Mega, Uno, Mini, Nano. Boards like Leonardo, Esplora and Micro, with the USB directly managed by the microcontroller, don't need the capacitor.