I had the same problem during the change of my K310i into W200i. When I flashed the phone and uploaded some patches, the first boot was unable to complete - after a couple of minutes phone have reseted. After that I realized, that the best way to flash the phone and upload any patches is to do it in two steps:
1. Flash your new firmware, run the phone, so it may properly alocate in the memory.
2. Upload patches you want to apply, than restart the phone.

I hope it will help.