I opened up my RCB6i today to try and add an LED and now I am facing a big problem  There appear to be two wires that jumper two contact points on the circuit board to inform the processor that it is mode 2. However, those wires have come off and now my only option is to put a permanent jumper. I can't even switch the mode in the software menu since Mode 2 is not available unless the jumper is there. I wanted to ask if anybody knows which contact points need to be jumpered. There is something called ZYS and there is a GND pad as well. I have attached the photos.

Problem fixed. I just had to jumper those two big solder pads visible in the photo. My Tx is locked to Mode 2/4 now but I don't really care. I could probably try and add the switchable feature back later. Now it's time to add an ON indicator LED.

But what is the purpose of LED

The LED is just to tell you not kill the lipo!!

It already has low voltage alarm.

yup!! but the LED will remind you to turn the radio off after every use and not when the lipo is almost down!!

Yup. While working on my quad or planes it is easy to do some testing and then go back to the workbench leaving the Tx on. It is not such a big deal since I am using NiMH cells but I opened the transmitter up anyway so I might as well install it. I will put some pictures of it. BTW, my elevator stick is feeling kind of 'sticky' now. It does not spring back so easily every time. Any idea what the problem could be?

the spring not working properly or something making it not work properly!!

I will check. It must be the way I put it back together.

see if any wires is blocking action of spring - nothing else is gonna be the reason