I have an S5830i that was given. When i got it, all it was doing during the startup was show RZ and a loading bar and then RZ and the loading bar again. I finaly managed to get it into download mode and flashed a stock Samsung ROM using ODIN, after ODIN has flash then phone restarts and on the next screen that is pretty quick I some of the following
something that mentions CSC
Failed to mount /data rebooting
I tried to go into the recovery mode to clear the data (factory reset) and i get failed to mount /data.
The phone is now bootlooping - is there a way to fix this