diff --git a/Makefile.p690 b/Makefile.p690
index f7111d8b5c054d4bdff0dfec23827805f956c3c0..1197115cdd35f342ebcbe0f10c53bf90783d7c47 100644
--- a/Makefile.p690
+++ b/Makefile.p690
@@ -45,19 +45,19 @@ FLG64=-b64
 # -qflttrap=overflow:underflow:zerodivide:invalid:NANQ:enable 
 
 # take -qextchk out for the final compile
-# change -qhalt=e to -qhalt=s, after verifying that the errors
-# all come from MPI calls.
+# Need -qhalt=s, else the compiler stops on the multiple errors from MPI calls.
+# For no optimzation, use "-O0" and remove "-qstrict"
 FFLAGS  = -g -O2 -qstrict -Q $(BITS) $(FLG64) -qarch=auto -qtune=auto \
 -qmaxmem=-1 \
 -qcheck -qwarn64  \
 -qfloat=nomaf:nofold:norsqrt:strictnmaf \
 -qflttrap=overflow:underflow:zerodivide:invalid:NANQ:enable \
--qsigtrap \
--qhalt=e -qextchk
+-qsigtrap -qnosave -qhalt=s -qextchk
 
 # Define C compiler flags.............................
 #
 # take -qextchk out for the final compile
+# For no optimzation, remove the "-O" option and remove "-qstrict"
 CFLAGS  = -g -O2 -qstrict -Q $(BITS) $(FLG64) -qarch=auto -qtune=auto \
 -qcheck -qwarn64 \
 -qfloat=nomaf:nofold:norsqrt \