Firmware is computer software that is programmed permanently in your computer. As long as you know the model of your computer and the manufacturer, you can go to the manufacturer's website. The manufacturer's site should have specific details on updating firmware for your equipment.
https://www.blackberry.com/Downloads
If you are referring to the PSP then just do a search for psp 3.52 firmware downloads. You should find the links for this pretty easily.
Firmware updates are specific to certain models of Macs. It's possible that the firmware you're trying to install is not the correct firmware for your particular Mac. If the firmware was downloaded by going to  -> Software Updates (or just by running Software Update), then the firmware is likely the correct version, and may just be corrupt. If the firmware was downloaded from Apple's Support Downloads, then it is most likely the incorrect firmware for your Mac.
kundi
This site seems to have a tutorial. See if this will help:www.gtagaming.com/downloads/installation-help
You need the latest firmware. go to this site to download it select the t10 and download the firmware.
If you don't have a memory card, you've got nothing to save the downloads onto. The PSP's own internal memory is only for system settings, and its own firmware.
i have an itouch jailbroken with 3.0 i didn't install 3.1.2, but i don't think it will do something to it.
Go to the apple inc site for the lastest OS
www.mp3skull.com is.
www.watchmoviesonline.com
What sort of downloads?