Leo, will we also know where the keys where actually stored and what was the funcion of each custom on the B Board? Just curious....
That I can tell you right now:
DL-1827 (CIF, I presume Character InterFace)
Controls the CPS2 sprite generator hardware. Has 16KB/16bit of SRAM connected to it, divided in two banks of 8KB/16bit. 16KB is enough to take two sprite lists which are swapped every frame. CIF also is part of the interface for keys upload. It's unknown at the time how the keys are uploaded to SPA from CIF.
DL-1525 (SPA, I don't know what SPA means)
This is a custom Motorola chip which has the 68000 core and the cryptographic engine. Keys are stored here.
DL-2027 (CGD, I presume it is Character Generator Data)
Do de-interleaving and splitting, latching of graphics data. The CPS2 re-uses all of the CPS1 graphics subsystem, (all but the sprites) so the CGA/CGD chips are supposed to translate the new roms into the old format that CPS A and B chips need to function (for the scroll layers)
DL-1927 (CGA, I suppose it means Character Generator Address)
Works in pair with CGD, latches addresses within the graphics ROMs.