The dual screen bb1's require a processor for the top lcd, unlike the bb1.5 where both monitors are driven by the BB2 mpu. So the conversion depends on which way you want to go. The easiest way is to just obtain a topbox from a dual screen bb1 that is being parted out, complete with the top monitor and associated processor board (also known as a TseTse board). Then the conversion is simply swapping out the top box from the one you have and connecting the harness that come out of the the tsetse board and power cables.