If you tell me what you’re actually trying to do (play a specific game on PC? fix a real console? learn how emulation works?), I can give you a more precise, safe guide.

Microsoft provides official system update files that can be downloaded to a USB drive (formatted to FAT32) to update consoles that cannot connect to the internet. You can find these on the Xbox Support site Modded Consoles:

If you’re looking for information on legitimate topics related to Xbox 360 firmware, such as:

He pressed A. The ghost of his father raised its sniper rifle, and together they walked into the next loading zone.

: A recent major feature is the Bad Update hypervisor exploit, which allows you to run homebrew and unsigned code on any unmodified Xbox 360 via a USB drive without opening the console.