General :: GT-I8160 Stuck In Startsplash?

bought a used Samsung GT-I8160 (Galaxy Ace II) on Tuesday. It is without simlock and not branded. Originally it had Gingergread installed. I tried my SIM and after some fundling it in the slot it finally worked, I got connection, could recieve and send messages and use the Internet via the browser.

After that I tried to get it rooted via Odin v3.07, I8160XXLL2_CWM_5.0.2.6_ANT.tar.zip and UPDATE-SuperSU-1.65.zip wich worked. So I went on and tried CM 10.1 and 10.2 and Vanilla RootBox Build 4m which all worked extremely well. Just a single glitch: I could not get it to recognize my SIM any more. Even with holding it in place for better connection to the contacts to the chip. Remembering, that it once worked I thougt to flash the stock rom (via sammobile.com) back on and tried I8160XXLL2_I8160ATOMA1_ATO.zip which succeeded in Odin but brought me to my final problem.

The Problem:

Right now while booting or booting to recovery it gets stuck on the first screen, which is a Samsung Startsplash or a black screen or a frozen loading circle. Therefore I can not enter any codes or wipe any data through recovery.

I can start the phone in Odin Mode and flash custom roms, stock roms, kernels and whatever, what gets a succeed and a PASS! in Odin, but changes nothing for re-booting while flashing or booting manually into the other modes.

Searching the Internet I have not found a solution and even the problem seems to be rare. As last resort I tried to flash the GT-I8160_EUR_XX_4G.pit as mentioned in one post while Re-Partition through Odin, what did not change a thing. I guess I did something awefully wrong on the way but would like to get it undone. If there is no solution to do it myself I will have to go to a store next week.