I scratched off part of the code on the back, the first 4 digits. How can I find the missing digits. Please help.

SOURCE: forgot my 4 digit sercurity

You can do this by performing a hard reset of the psp system.
You can do this by following the instructions below.
1.Remove the battery from the left side of the PSP while it is still on. The unit will power down instantly. Wait 10 seconds and then replace the battery.
2.Press both clear shoulder buttons at the top of the PSP and keep them held down while the PSP reboots. This initiates a "Recovery" mode.
3.Press down on the control pad to locate a "recovery" folder. This will contain all of your PSP content, including games, music, videos and podcasts that are saved on the device. Highlight this folder and press the "X" button to begin reinstalling your content.
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