minicom is the terminal programm under linux, similar to hyperterm under Windows.

On Debian based systems install minicom and the also nessesary xmodem transfer program as root with

apt-get install minicom
apt-get install lrzsz

Start minicom as root on command line with an configuration name as argument

minicom eddi_ttyS0

This will save your minicom configuration as /etc/minicom/minirc.eddi_ttyS0, if you select Save setup inside minicom. Once you have made the right settings you can reload them in further sessions using the same command.

After minicom ist started, press Ctrl-A for command mode an then O for COnfigure. Make now the following settings:

• Filenames and path ⇒ Uploads: Path to your firmware images, for instance trunk/openwrt/bin
• Serial port setup ⇒ serial devive: for first or second serial port on your PC /dev/ttyS0 or /dev/ttyS1
• Serial port setup ⇒ Bps/Par/Bits: 115200 8N1
• Serial port setup ⇒ Hardware-Handshaking: No
• Serial port setup ⇒ Software-Handshaking: No
• Modem and dialing ⇒ Init-String: nothing
• Modem and dialing ⇒ Reset-String: nothing
• Save setup as eddi_ttyS0 : <ENTER>

After you have pressed a in the original or 1 in the Extended bootloader press Ctrl-A and then S for Send. A menu appears, where you have to select xmodem. Then the file select dialogbox should appear. You should already be in the directory you have entered during the minicom setup desribed above. Seleting the firmware file should start the upload.

If the xmodem transfer to the bootloader won’t work you are not alone with this. There is no general solution, but try the following:

• after starting the xmodem download at the bootloader type 5...10 chars of junk into minicom before you start the upload in minicom
• after starting the xmodem download at the bootloader wait 5..8 sec before you start the upload in minicom
• plug your router of and on and try the xmodem transfer after power on before your router boots into the old firmware
• try to use download script