Boot Process

When an embedded Linux device boots slowly, an application does not start, a driver does not load, or a network service fails, people often jump straight to application logs.

But the application is only the last part of the boot chain. After power-on, the CPU does not directly jump to business logic. It starts from a fixed entry, initializes the minimal hardware environment, enters the bootloader, loads the Linux kernel, Device Tree, and rootfs-related information, waits for the kernel to reach user space, and only then reaches the application.

When a device boots slowly, an application does not start, a driver does not load, or a network service fails, people often jump straight to application logs.

But the application is only the last part of the boot chain. After power-on, the CPU does not directly jump to business logic. It starts from a fixed entry, initializes the minimal hardware environment, finds the next-stage image, loads an OS or RTOS, initializes memory, devices, and scheduling, and only then reaches the application.