Juggerknight,
Keep the boot block recovery jumper on pins 2 to 3 of E15. This is "off" because pin 3 is not connected. Putting the jumper from pins 2 to 3 "parks" the jumper. Putting the jumper on pins 1 to 2 activates the boot block recovery mode, and the system will not boot with the jumper in this "on" position. (You already found this out)
Also, do not mix unbuffered and registered memory in the same system. Use only one or the other.
