The RP/M monitor, as I am sure you know behaves like a cassette based CP/M and so the transient area starts at 0100. Would the following code, loaded at 0100h be enough to pulse the IVC's CPU reset from the CPU Board?
Code:
21 B3 00 loop: ld hl, 0x00b3 ; port B3
7E ld a, (hl) ; read
77 ld (hl), a ; then write
18 F9 jr loop