... download and install bootloader v 7 from the FlashMagic site, which has multiple options for bootloader entry, including entry upon pin pulled, and no bootloader entry (documentation enclosed in the zip).

Or, modify the bootloader yourself - if you search for "Waclawek P89V51RD2 bootloader" ;-) , you will find enough clues how to do it.

NXP's documentation and public support on their '51 derivatives appears to deteriorate steadily in the last few years. A quick search on these chips just now revealed, for example, that they list the '51 derivatives among others under "2-Wide 2-Input, 2-Wide 3-Input AND-OR-Invert Gates", together with the 74F51 "true gate" (I don't know how to put a half-smiling, half-crying smiley here).

JW

PS. Always indicate the full name of the IC, including the prefix indicating the manufacturer, as there might be derivatives around by other manufacturers with the same name and different features.