where your program looks like 
<i>org 0
ljmp xxxyyy
...

xxxyyy:</i>

change to
org 0
ljmp bootck

bootck:
jb  P3.1,xxxyyy ;TxD always high without cliplead
     mov  AUXR1,#020h  ;enable boot
parametres for set boot vector as in AN 461 pg 14
     call 0fff0h
parametres for set status byte as in AN 461 pg 14 
     call 0fff0h
     jmp  $            ;wait for reset<i>
xxxyyy:   as in your original code</i>