No-one knows for sure but there are rumours, rumours and more rumours.
Thsi is from a post by Ivac on the $lybusters forum:
There are now 2 conflicting camps about the chip type of the
Sky Gen1 and Gen2 cards.
-----------------------------------------
theory-1 (less likely)
supporters: nissan@$lybusters, scuby@elmax
Sky Gen1 : TI TMS370C
Sky Gen2 : SLE66C80S
-----------------------------------------
theory-2 (more likely)
supporters: dean556 + various unnamed sources
Sky Gen1: SLE44(C80S ?) like H, GL11, GX15, GX17, Towitoko P64
Sky Gen2: TI TMS(370C ?) like HU
Does this help?
PaulR