Problem after flashing ECU
 

I have a European 2019 MT BRZ. It has a catless header and catless frontpipe.

It's running a modified ZA1JK00G rom by wayne and the car pulls great and sounds really loud. Unfortunately I have to take it for a MOT inspection.

The first thing I've done before putting back the original catted header and frontpipe, is flash the original rom it had, which is a ZA1JQ00G. I couldn't find it so I downloaded it from Steve's tactrix thread. I successfully flashed it using tactrix and turned on the car.

Now the car sounds really really quiet, almost as stock, even with both catless header and FP. How is this possible? It doesn't make sense to me.

I checked the rom I downloaded with a hex editor and compared to my own stock rom. They both seem to be identical and have the same calid, but instead of having "00" in black spaces, it has "FF". Is that normal? Maybe the Q00G rom I flashed had something wrong that broke the ECU?

Attatched you may find both roms so if you guys could check them out, I'd be really thankful.

different cam timings and different tune overrall, your flashing hasn't broken anything