Official u-boot firmware doesn't have fastboot

I downloaded the u-boot firmware from khadas site( - Index of /firmware/VIM3L/Uboot/) and flashed it to my vim3l board, and it booted as expected, but the u-boot REPL shown by this firmware doesn’t have the fastboot command. This is the serial output displayed when I boot into this firmware and run the fastboot command: u-boot output · GitHub