After hackers found a security flaw in the original Japanese release of the PSP, Sony has taken measures to fix that hole with a required BIOS update for older models of the PlayStation Portable.
As Ign reports...
"...This new update requirement (which does not affect any model of the PSP released in America -- all North American PSPs were released with 1.5 system software, whereas the security hole was only in PSP v1.0) affects older PSPs when gamers try to play newly-released games.
A message pops up on the screen stating, "This game could not be started. To start, you must update the system software." A simple BIOS update (which can be done either with the online Network Update feature or with a BIOS updater written on new game UMDs to bring the system up to the more recent PSP version (an even more recent 1.51 has also been released, with yet another security patch, although unless 1.50 has an extremely compromising security hole, Sony may settle for 1.5/1.51 updates with game releases until it has a better and more necessary BIOS update to offer.)
This security update is a vital flaw fix for Sony. Although most gamers would never notice, the security flaw leaves the PSP open to run software not carrying Sony's official digital encryption signature. Basically, it leaves the PSP wide open to run bootlegs and possibly pirated games. An emulator for running Game Boy and Game Boy Color games on PSP has already been converted to run on unprotected PSP hardware, and while coders have so far not been able to figure out how to run stolen PSP games, the encryption flaw could be used to run the illegal rips of PSP games already posted on international pirate sites.
The first game released in Japan to include the version checker is the new Space Invaders Pocket compilation, a collection of Space Invaders games from throughout its years. It's likely that this will be a standard feature in games released for PSP from now on -- the next set of games to come out for PSP after this week's Space Invaders is the Yarudora Pocket series of adventure games from Sony, which ship on May 26.