I booted my phone(Galaxy i7500, PDA: I7500DDII3, Phone: I7500DDII3, CSC: I7500DDII5) in the download mode(Vol. down + OK + End call), and then removed the battery to shut it down(didn't do anything to phone in download mode). Next thing I know my sim card is not recognized anymore. Other sim cards were working fine with my phone, so I decided to get my sim replaced. Even the replacement sim doesn't function well(for 20 min. after restart it functions properly, but then it abruptly starts displaying 'Not registered on n/w prompts'). Even factory reset doesn't seem to solve this problem.