ATTENTION! Bootloader upgrade is a risky operation and should not be performed unless absolutely necessary! If anything goes wrong during this process (power shortage, mistype, etc.) the board will be BRICKED (broken). Keep in mind that warranty does not cover Komikan module if it is damaged due to user's fault.
sudo apt-get install tftp-hpa
2. Connect to device via picocom.
picocom -b 115200 /dev/ttyUSB0
3. Reboot device and enter bootloader menu by pressing ESC several times while device boots.
4. Check for ip address.
5. Exit from picocom, return to PC shell. Press <CTRL+A> <CTRL+X> to exit from picocom.
6. Add address from the same subnet as device address.
sudo ip a a 192.168.1.5/24 dev eth2
7. Execute this recovery command.
tftp 192.168.1.6 -m binary -c put <uboot>
8. Komikan should write new bootloader in a few seconds.