SP-S2
SP-S2 is the name of the 128KiB ROM containing the 68k code for the BIOS embedded in some MVS systems.
It's mapped in the 68k's address space from $C00000 to $C20000, and mirrored over to $D00000.
The dump is named sp-s2.sp1 in BIOS sets.
See BIOSes.