The defining feature of the 9000x series—specifically those manufactured from late 2008 onwards—is a new BIOS (v2.30) The Modding Barrier: This BIOS update patched the exploit used by FreeMCBoot (FMCB)
By removing the bulky external power brick found in earlier Slims (like the SCPH-700xx series), Sony achieved a total weight of only 720 grams . scph90006+bios+new