⚠️ : Never use an official Microsoft system update on a modded (JTAG/RGH) console . An official update will overwrite your custom NAND with a default one, a process that will 'brick' the console, rendering it completely unusable. Modded consoles require a special patched version of the update created with a tool like J-Runner.

Because the Xbox 360 has a complex security ring and a hypervisor, Xenia developers chose to re-write the kernel functions from scratch rather than rely on a dumped NAND file.

The Ultimate Guide to Xbox 360 BIOS Downloads: Myths, Reality, and Emulation