The IDPS is a 16 byte value that contains console specific information. Exactly what information this stores is not completely known.

Structure

00000000  00 00 00 01 00 89 00 0B 14 00 EF DD CA 25 52 66  .....‰....ïÝÊ%Rf
                         ^^    ^^

6th byte represents your Target ID

8th byte represents your Motherboard_Revisions // possible sku model

0x1 = CECHA (60GB Full PS2) - COK-001 + Memcard Daughterboard
0x2 = CECHB (20GB Full PS2) - COK-001
0x3 = CECHC (60GB Partial PS2) - COK-002 + Memcard Daughterboard
0x4 = CECHE (80GB Partial PS2) - COK-002W + Memcard Daughterboard
0x5 = CECHG (40GB No PS2) - SEM-001
0x6 = CECHH (40GB No PS2) - DIA-001
0x7 = CECHJ / CECHK (40GB/80GB No PS2) - DIA-002
0x8 = CECHL / CECHM / CECHP / CECHQ (80GB/160GB No PS2) - VER-001
0x9 = CECH20A / CECH20B (120GB/250GB Slim) - DYN-001
0xA = CECH21A / CECH21B (120GB/250GB Slim) - SUR-001
0xB = CECH25A / CECH25B (160GB/320GB Slim)

The IDPS can be found in EID0 and EID5, see Flash

IDPS