Recently bought a 2008 135i. Flashed MHD and xHP. Before I never tried the paddle shifters so I'm not sure if they functioned correctly before. But in manual mode both left and right paddle shifters change the gear up. If I use the gear stick that shifts down and up as expected.
Any ideas? Maybe wired wrong internally? Or is it software based. I have Carly bmw also and can't find any reference to shifting in there