Adding a temporary change in the maintenance patch area of an O/C/EOV module

A maintenance patch area is included in each O/C/EOV object module as the result of the expansion of the XCTLTABL macro. The maintenance patch area is 5% of the size of the object module and is located at the end of each module, immediately preceding the 8-byte module name. You can use the AMASPZAP utility to add a modification to an object module:

Locate the transfer control table in the source code.
Locate the maintenance patch area in the transfer control table. The beginning of the patch area is the third label from the end of the transfer control table (and the end of the module).
Using the displacement (location-counter value) of the maintenance patch area, verify that the patch area is all zeros, and apply the modification to the object module.

Note:

Remember to perform a cold start of the system after the alteration. A warm start will not reformat the PLPA to include your modification.
Unresolved V-type address constants (VCONs), which are 4 bytes of zeros, sometimes immediately precede the maintenance patch area. Be careful not to modify the VCONs when adding a patch.