Hi Will, About the message, "Unknown command 'bootelf'", it seems that this command wasn't configured and compiled. You'd better recompile th u-boot image. You can modify the source code to config this command. Add a macro define "#define CONFIG_CMD_ELF" in the file "include/config_cmd_default.h" to enable the command "bootelf". This link can help you, http://elastos.org/redmine/issues/17472#change-34139. Lucky! -- Jensen Zhang Tongji University