After looking at the Schematics for the Hannah and April, I see that you are using pin 6 (vss2) as the pin you expect a ID code to come from. What is this was GND? I'm looking at trying to hack 2 boards that have an SD card slot, but where I have access to the pins. Unfortunately pin 3 and 6 are tied to GND, as Vss1 and Vss2) the cards are https://www.digilentinc.com/Products/Detail.cfm?NavPath=2,401,513&Prod=PMOD-SD
which is really an I/O card connected to a SD card slot. Typically this would connect to a Xilinx FPGA card through General purpose I/O, so it could look just like a April card, except that it would not have the Atmel Id chip on pin 6. (yes I could hack it and add it, but that is not the goal.
The other card is a Xilinx Kintex-7 KC705 board, but it has exactly the same problem. https://secure.xilinx.com/webreg/clickthrough.do?cid=188020&cancellink=http://www.xilinx.com/support/documentation/index.htm
Is ther a way to provide an ID from the other Data pins? Typically on FPGA boards, we imbed a Mac address or other ID in the FPGA code, so it's changeable.