How to Update PSP Slim to V3.90.

Right after you download the firmware at http://download.daniusoft.com/psp-download/PSPV3.90.rar , extract your PSPV3.90.rar file and look for a file called EBOOT.PBP.
Link up PSP Slim to microcomputer with the USB port, open up your memory stick, just go to the 'GAME' folder, make fresh folder called as 'UPDATE', move the EBOOT.PBP then put it on.
Immediately, switch on PSP Slim, just go to Game -- Memory Stick, you will find the update file:


Hit 'Enter' key to open that file. It will show your directions regarding the way to complete the update procedure.

Notice: be sure your battery has no less than fifty percent power when you start to update.
When update completed, you are able to go to Settings > System Settings > System Information to confirm the firmware version of the PSP Slim. If you do a proper update, it will show the System Software Version as 3.90.