hi,
I'm using the AT89S8252...
I'm using the bottload (I find it in phillips.com) program for download the program from the PC...

Could you say more about that program you have downloaded from Philips?

As I know:
1) AT89S8252 is Atmel`s product and has nothing with software created by Philips;
2) AT89S8252 has not bootloader inside and even is not able to write itself (no API, no hardware, etc);
3) AT89S8252 may be programmed with two ways:
- via parallel programmer;
- via ISP hardware which based on SPI and may be invoked during AT89S8252 is in reset state.

So I do not understand your question completely,

Sorry,
Oleg