You have probably heard about the so-called firmware hack for version 1.51 if you have been browsing the web for PS3 news. If not, let me inform you.
There have been numerous claims on the web about a 'hack' for the FW 1.51. It turns out that this is not entirely true. The so-called 'hack' for the firmware has not turned out to be a hack but more of a network update bypass, at best.
The mod is pretty much only any good if you spend all of your PS3 time browsing the Playstation Network Store.
You can now access the official PS3 store without updating your current PS3 Firmware version! - Only for now.
You can now play PS3 games on-line, without updating your current PS3 Firmware! - Fake.
You may be able to downgrade the PS3's Firmware through this circumvention technique. - Fake.
You may be able to 'install' your own desired PS3 store items using this method. - Fake
The only good this mod will do for you it seems is lets you browse the PSN Store without updating your firmware. I really don't see the benefit to this whatsoever. At this point in time the network updates are required to do pretty much anything, such as playing games online.