Use U-Boot

• Device Firmware Upgrade (DFU)
• Device Tree Overlays
• Network console
• Partitions

Shell commands

• addrmap command
• base command
• bootefi command
• booti command
• bootmenu command
• button command
• conitrace command
• echo command
• exception command
• exit command
• false command
• for command
• load command
• loady command
• mbr command
• pstore command
• qfw command
• sbi command
• true command