Ubiquiti LocoM2W u-boot limitation

Hello there, I've got an ethernet damaged board and I want to try to transfer openwrt firmware using kermit over serial. I've soldered four pins over J5 holes and I can access to u-boot console using an Arduino One with hardware USB TTL configuration. All go well but you boot doesn't admit file transfer using kermit or ymodem. There are no loady or loadm commands. How can I do it?


Replace the bootloader.

What options is the uboot offering?
Post the output of the help command.