Hi,
sad but true. After reading tons of threads at xda-developers I come to the conclusion that there is no way to bring it back to life. At least not for mortals like me. It is not 100% dead though, because the LED is still orange or green or blue (after starting it with trackball pressed). But there is no reaction from a PC regarding USB.
But I think i do know now what went wrong at first place. I put this one as goldcard.img on the SD: ROM v2.53.707.2 (Engineerings SPL v1.33.2010) - MD5 : F9674D19BE5F949D0D9DC99714D210E3. Alas it is for 32A devices and so I turned my 32B into a 32A-ish 32B.
All right, then next level, which is poking the phone shop's service
electric-sheep-reloaded