There is a good thread here – http://www.modelflying.co.uk/forums/postings.asp?th=104775&p=2
The 4 things I would add are :
1) do not power your receiver from a battery. It will get power via the USB cable.
2) you will need to make an adapter using the small molex (?) plug supplied when you bought the receiver. Use the yellow, red and black cables.
3) The software tool you need is a pig to find. Look for the “Upgrade Lite-S.Port Telemetry” under Download > Tools
4) Be careful – there seems to be both the original EU firmware and a “bug fixed” version of the firmware on the site.
Note : you will need to re-activate your failsafes again after flashing the firmware – even if you configured them via the Tx or OpenTx Companion.
Hope that this helps, Sean