This topic covers few methods how to upgrade firmware on Carambola. Some methods require only serial connection, some only LAN, some LAN and Serial. Also you might need to install/setup other software to perform these tasks.
sysupgrade is best ever way to upgrade firmware. For this to work you must be connected to Carambola terminal. It does not matter using Serial, LAN ir Wireless connection.
mtd method is similar to sysupgrade. Use any one you like.
Using serial cable is most dangerous one. There many things that can go wrong. Ensure you have good serial cable (cheaper usb-serial adapters don't work), rock solid power supply and steel nerves :)
TFTP method to upgrade firmware requires you to have serial connection to Carambola and configured TFTP server over LAN. Wireless connection does not work. This tutorial might help setting up TFTP server
If for some reason you have older bootloader and wish to upgrade, you must proceed here. It is even more dangerous than upgrading firmware using serial connection only. If something fails, there are big chances you render your module useless.
This method is recommended for novices. Connect Carambola web interface, browse for firmware upgrade, select file and press upgrade.