Repurposing a TL-WR542G

Preamble

I was given one of these by the owner of my block of flats, as he has a room full of old Wi-Fi routers (including LinkSys WRT54G), due to continual upgrading of the in-house WI-Fi network… I want to use it as a Ethernet switch. Also in Wi-Fi client mode, as a Wi-Fi bridge (i.e. like a USB Wi-Fi dongle, basically Wi-Fi to Ethernet – for a laptop without wireless capability).