It's the way they are manufactured, They use a chip that they program using a UV Writer and a base map that they modify to the specs of the car and they never released the program or base map, so there is no way to do it without them
Yeh it's not that hard to install a daughter board. But it's not really re-programmable.
Most unit out there have a base map on for boost up on a ct9.
A few units out there have been re-flashed and yes they would need your ecu and car in japan to do this. I know knightsports ecu for the rx7 are similar, alot of US owners got together and got knightsport to tour the usa reflashing ecu's. Maybe if there are enough people that wanted it done you could get jam to come to the uk, but it would take alot of people i would have thought.
its just a normal chip. so if you had the facilities to read the information on it and decipher it then you could probably get any tuner to remap it.
in theory you could quite easily reproduce your own daughter boards and sell them as a kit for people so they can have an uprated ecu. would need to be able to get hold of the parts, produce printed circuit boards and program chips.
It should be able to composate for that, Mine Runs a CT9 at .9 bar and 1 bar, Exhaust, Manifold and FMIC and still over fuels a bit, it's self trimming ot an extent