On closer inspection I was able to identify the specific code that opens the nag screen and prints the message. It's interesting that everything is done with internal amos.library calls. I wasn't aware that these were documented back in the day. The equ.s file on the AmosPro tutorial disk has the equates for these functions but doesn't explain the input parameters. The note at the top of the file just says "Be patient, we will soon (I hope) publish informations about the functions of the amos.library."
L0 MOVEM.L A3-A6,-(SP)
LEA (MB,PC),A3
MOVE.L A3,($1B8,A5) * store address of datazone
LEA (default,PC),A0
MOVE.L A0,($1BC,A5) * store address of default/run routine
LEA (default,PC),A0
MOVE.L A0,($1C0,A5) * store address of cleanup routine (same as default/run)
MOVEM.L (SP)+,A3-A6
MOVEQ #12,D0 * Move extnb-1 to d0 - extension loaded OK.
RTS
default LINK.W A3,#-$20
BSR.W nagscreen * bsr to nag screen routine - replace this with $4E714E71 to skip
dl $FE31001D * AmosPro Rbsr
dl $FE31000A * AmosPro Rbsr
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nagscreen MOVEA.L ($1B8,A5),A2 *Dload flag from datazone
ADDQ.L #1,($5D4,A2)
BEQ.W lbC00091E *Skip nag screen if flag set
MOVE.L #6,-(A3)
MOVE.L #$140,-(A3)
MOVE.L #$C8,-(A3)
MOVE.L #4,-(A3)
MOVE.L #0,-(A3)
MOVE.L (A3)+,D5
ANDI.L #$8004,D5
MOVE.L (A3)+,D6
MOVEQ #1,D4
MOVEQ #2,D1
lbC00083E CMP.L D1,D6
BEQ.B lbC00084C
LSL.W #1,D1
ADDQ.W #1,D4
CMP.W #7,D4
BCS.B lbC00083E
lbC00084C MOVE.L (A3)+,D3
MOVE.L (A3)+,D2
MOVE.L (A3)+,D1
LEA ($95C,A5),A1
MOVEA.L (-8,A5),A0 * EcCall Cree (See wequ.s and equ.s)
JSR (12,A0) *
MOVE.L A0,($52C,A5)
MOVE.W ($BC,A0),($52A,A5)
ADDQ.W #1,($52A,A5)
MOVEA.L (-8,A5),A0 * EcCall CopForce
JSR ($20,A0) *
MOVEQ #5,D2
MOVEQ #0,D1
MOVEA.L (-12,A5),A0 * WiCall Locate
JSR ($10,A0) *
LEA (PowerBobsV10.MSG,PC),A1
MOVEA.L (-12,A5),A0 * WiCall Centre
JSR (8,A0) *
MOVEQ #7,D2
MOVEQ #0,D1
MOVEA.L (-12,A5),A0 * WiCall Locate
JSR ($10,A0) *
LEA (Unregisteredv.MSG,PC),A1
MOVEA.L (-12,A5),A0 * WiCall Centre
JSR (8,A0) *
MOVEQ #9,D2
MOVEQ #0,D1
MOVEA.L (-12,A5),A0 * WiCall Locate
JSR ($10,A0) *
LEA (PowerSoft.MSG,PC),A1
MOVEA.L (-12,A5),A0 * WiCall Centre
JSR (8,A0) *
MOVEQ #13,D2
MOVEQ #0,D1
MOVEA.L (-12,A5),A0 * WiCall Locate
JSR ($10,A0) *
LEA (PresstheEnter.MSG,PC),A1
MOVEA.L (-12,A5),A0 * WiCall Centre
JSR (8,A0) *
lbC0008D4 MOVEA.L (-4,A5),A0 * SyCall WaitVbl
JSR ($5C,A0) *
MOVEA.L (-4,A5),A0 * SyCall InKey
JSR (A0) *
CMP.W #13,D1 * Has chr$(13) been entered?
BNE.B lbC0008D4
MOVEQ #6,D1
MOVEA.L (-8,A5),A0 * EcCall Del
JSR ($10,A0) *
CLR.W ($52A,A5)
CLR.L ($52C,A5)
CMPA.L #0,A0
BEQ.B lbC00091E
MOVE.W ($BC,A0),D0
CMP.W #8,D0
BCC.B lbC00091E
ADDQ.W #1,D0
MOVE.W D0,($52A,A5)
MOVE.L A0,($52C,A5)
MOVEA.L (-8,A5),A0
JSR ($20,A0)
lbC00091E RTS