What happens if I supply the Lime A20 with 48V?

[babylis]

Actually, I know the answer to this: it fries the board 

I used a PoE splitter to generate 5V/2A on the barrel connector. Except.. splitters generally aren't isolated and they actually float the voltage much higher. Not a problem unless you connect a FTDI UART to USB cable and ground it on the UART0 pin. Then you get a nasty buzzing sound, a dead board, a dead FTDI cable, and maybe a dead USB hub or a dead USB card on your PC..

Now, my final question is: will Olimex replace my board under warranty? (Only joking..)