Help Download mode is changing into recovery mode in samsung galaxy s

[Samdan]

I am running korean anycall samsung galaxy s with froyo 2.2.1. When i go into download mode using 3 button (volume down+home key+power button) there appears a sentence do not turn off the target in korean. Just after that (2 or 3 seconds later) download mode changes into recovery mode automatically. I have been trying it for ~10 times but still no success entering download mode properly. Ahh.. also when it is changing from download mode into recovery mode there comes "movi_checking..." or something like that and there is the freaking recovery mode. Here is the fun part. when i hold volume up+home key+power button phone just boots instead of going into recovery mode. Tried youtube and saw usb jig that can manually make the phone enter download mode. But i think it will not affect 2 or 3 seconds appearing of download mode. Please sum1 help me solve this problem, if you had problem like mine.