I have a spare Mega 1280 where the serial input line is bad.

So how to program it with no FTDI serial0 input ?

Notice the ISP pins in lower left ?? Thats how !

I use a program called eepc that is used to reprogram the er9x R/C TX. It does it via a $14 usbtiny ISP device from Sparkfun. Google for the er9x firmware update.

The Arduino program compiles a hex file you can use with the eepc program.(hold down the shift key and do compile in arduino. See where the hex file ends up and use it for ISP.)

Use the -F override in eepc to program the m1280 chip with m64 setting.

So if your program doesn't need serial0 input, here is the way to program and get arround the blown input pin.