Bootloader Arduino

svp j'ai une question, est-ce-qu'on peut modifier un bootloader d'une carte Arduino Uno si oui comment le faire.
et merci !!!

Connect it to an ICSP programmer and upload the bootloader.

If uploading standard bootloader, you would select the programmer you're using from tools -> programmer and do burn bootloader.

For some other bootloader, you'd have to invoke AVRdude from the command line (google for details on the avrdude command line options - you can probably find a page written in french)

You posted in the english language section. In the future, please either post in english, or post in the french language section of the forum.