To patch RUNPCD ver. 2.4.4, CPM installation 3.1 to 3.1a, do:

Loc.	Was	Is
174	0	2a
175	0	94
176	0	3b
177	0	eb
178	0	c9
389	76	33
38a	33	2e
38b	2e	31
38c	31	61
528	50	cd
529	59	74
52a	d5	01
52c	94	92
52e	eb	e5
16dc	fb	05
16dd	01	00

This allows system calls to return a 16 bit value.  Needed to
operate various RSXs.  Uses some of the patch space, so care
needed if installing timers etc.