Where does Aboot look for the boot system image at boot time?

Aboot is the Arista bootloader, which operates before the main EOS (Extensible Operating System) is loaded. To determine which EOS software image to load, Aboot reads a specific configuration file located in the switch's flash memory. This file is named boot-config. The boot system command, when configured in EOS and saved to the startup-config, instructs EOS to write the specified image path into this /mnt/flash/boot-config file. However, Aboot itself only reads boot-config directly; it does not parse the running-config or startup-config.

A. The running-config exists only in the system's RAM after EOS has successfully booted and is not accessible to the Aboot bootloader.

B. Aboot does not read or parse the startup-config. The boot system command in startup-config is read by EOS, which then updates the boot-config file for Aboot to use on the next boot.

D. The filename is incorrect. The bootloader configuration file is named boot-config (with a hyphen), not bootconfig (with an underscore).

1. Arista EOS System Configuration Guide: In the section on "Managing Switch Booting," the documentation states, "The boot system command specifies the system image file that the switch loads during its next boot sequence by writing the file name to the /mnt/flash/boot-config file." This confirms that Aboot's instructions are stored in boot-config. (Reference: Arista EOS 4.28.0F System Configuration Guide, Chapter: System Configuration, Section: Managing Switch Booting).

2. Arista EOS Central - Aboot Article: This official resource clarifies the bootloader's function: "The boot process is controlled by the /mnt/flash/boot-config file. This file contains the SWI command, which specifies the path to the EOS software image to be loaded." This directly supports that Aboot looks for a file named boot-config. (Reference: Arista EOS Central, Software > EOS > Aboot).