There are plenty of tutorials out in the internet with extensive explanation about the pros and cons of installing openWRT in a home router.
This tutorial is to meant to grab only the relevant steps of the installation process :
The table below is very important cause a common mistake will be to connect the TX to TX and RX to RX, however it is the opposite.
|Pin No.||USB Serial to TTL Adapter||Wire Colour||Home Hub Connection Point|
|1||n/a||White||boot_sel2 / R45 Pad|
|2||n/a||n/a||GND / Use the USB socket ground/case pin|
|3||TX||Green||RX / R78 Pad|
|4||RX||Red||TX / R77 Pad|
|5||GND||n/a||GND / Use the ground plane connection of the capacitor|
Turn on the device with boot_sel2 connected to GND and as soon as you see the terminal output below disconnect it from ground.
Type [C-a] [C-h] to see available commands Terminal ready ROM VER: 1.1.4 CFG 04 UART
And, follow this tutorial to upload the modifed boot loader image to the router.
It's been a bit of trouble to set the TFTP server on my linux distro.
A service was already running on port 69 and preventing
tftpd-hpa to start and it had to be stopped :
service inetutils-inetd stop