This plugin brings back the function that SONY removed in firmware 6.20 which was when you used WiFi the WiFi activity light would flash to let you know if the PSP is transferring data, but now when your using WiFi the activity light is just ON so you can't really tell if the device is transferring data or not.
Instruction:
Place BlinkLed into your seplugins folder, and add the address to your vsh & game text files.
(PSP) ms0:/seplugins/BlinkLED.prx 1
(PSP GO) ef0:/seplugins/BlinkLED.prx 1
Download
Source