allright, fixed it really in the last sec.
First of all I unplugged the second ram
Downloaded a file called "crisdisk_118.exe" from somewhere in the hope the included "WINCRIS.EXE" would help --> neg. Before I executed the "CRISDISK.BAT" I overwrote "PLATFORM.BIN" & "BIOS.ROM".
Note: This time I didn't overwrite "PHLASH.EXE" with the newer one from Sony.
Working Version: PhoenixPhlash Utility 4.0 Release 1.81
Sonys Ver: PhoenixPhlash Utility 4.0 Release 1.84 3A15
All efforts using a dos bootdisk (dr or ms) with aflash, autoexec.bat or uniflash (on the same pc of course) did not work.
By the way, somewhere found a file called "TPM_319733-002_rev3_us.pdf" , a service manual form dell and compaq (people who can read and write) which helped in solving the problem, too.
Good luck guy, hope this saves y'all 4 hours
Eh, btw 3.15 am ... greets from Germany.