One thing is that its Bcore appear clean and can't accept fw updates either service (winswup) or user updates from Siemens site, and another the ability to write with V_Klay. (if BootKey in V-Klay loader is correct and connects, it can write...)
But usually with option "Clean Bcore" in x65PapuaUtils one can get that result.
Actually Model Name, Hash, IMEI are cleared from Bcore...
Some operation has done on the phone...
Maybe function "Freeze" (using OTP IMEI in filed IMEI) could put missing things in Bcore (x65PapuaUtils). But to do this need have correct keys from before, especially Skey to get phone in 'FactoryMode'...
Maybe the suggested procedure to 'Recalc keys in flash' could work...
Also there is another procedure for difficult cases as described in AllBugSGold.rar
although you are NOT in such bad position....