I did the recovery. Back to 1.5, still having the lock screen.
kernel: 2.6.27 hojoong@sep-13 #1
build number: 76xxcsdcbalum6375
About the recovery,
how do I do it? I was not sure. What I did is:
volume down+ ok + power
wait until the download thing show up
press home (button on top of power?)
then I rebooted the device.