That is what the post before you asked, but was answered a few posts above HERE. If the PS3 is newer you can't unless you have someone with a hardware flasher downgrade it first. If it's an older model, the following instructions should be of use:
Installation:
0: Installable on all cfw 3.55 4.21 4.30 and 4.31 v3.2, 4.0, 4.1, 4.2
1: Have QA flag enabled and system update debug ON
2: Copy the PUP in your USB in PS3/UPDATE
3: From the XMB (CFW 4.31-cfw4.30-cfw421)
4: Update system
5: Update from support storage
the devs will have one in due time... just give it a few months i believe it will only be a few months... I state that hypothesis on the opinion i have set before myself: did sony abandon the ps1?? YES! did sony abandon the ps2??? kinda a lot actually.
and the big question WILL THEY ABANDON the PS3?? I BELIEVE SO!! to some degree.. and the devs will be hard at work making a ps3-jb and a newer ps4-jb right when it comes out!! Other than that this is great SGK
CFW 4.31 v7 FULL 4.31 NO SPOOF by SGK: 7ace5cab29e0d482dc951f3df2927dfc
FIX MultiMAN cat XMBSGK+ by SGK: 2747f1c2b91bc9c6ffa7fd2d8f3bbc97
To quote, roughly translated: Hi all voilla is that everyone has been waiting for some day in my CFW v7 with quite small correction and I see the changelog.
Changelog:
1: Adding Core OS 31.4 compiler
2: Adding and all self SPRX 4.31
3: Install PKG of displacement of below home manager
4: Change icon
5: Every option of my previous CFW its available
6 QA flag enabled
Installation:
0: Installable on all cfw 3.55 4.21 4.30 and 4.31v3.2, 4.0, 4.1, 4.2,5.0,5.1,5.2
1: Have QA flag enabled and system update debug ON
2: Copy the PUP in your USB in PS3/UPDATE
3: From the XMB (cfw4.31-cfw4.30-cfw421-cfw3.55)
4: Update system
5: Update from super storage