Here are the experiences you'll face while downgrading from 2.71 to 1.5.This is after you have all the required files.
1.As soon as you Enter the Photo you'll see a Red Screen.This means the Downgrading is on and not to worry.Just sit back. OR
2.As soon as you enter the Photo you'll see a Black Screen.This means the Code has not run and you should simply restart the PSP.(This happened to me 4 times) OR
3.As soon as you enter the Photo you'll get hanged then and there.You wont see any other screen just the PSP will be freezed.Now this time you need to hold down the power button and then restart.Not to worry.(This happened to me 1 time)
4.I got the Red screen after the above.
5.So after you see the Red Screen the Memory Stick will be blinking and after sometime the screen will go blank this means the downgrading is over.Simply Restart.
6.Now you're greeted with a Screen saying settings are corrupted and you need to press O.(My God,I had a heart attack seeing this)But not to worry just press O and the PSP will restart itself and you'll be greeted by the Settings.
Inshort remain cool and don't plug off and turn off anything and you'll have a sure successfull Downgrade.
So thats all.I hope it'll help some people.Mods if ya feel if this is useless then please lock it.