hi,

I’ve been working with this uc T89C51RD2 and now AT89C51RD2...
I found out that I need to program the bootloader of the uc Ooops!
ATMEL says: First download the latest software release of bootloader….

I do not know what EPSILON5 does, there is FLIP from Atmel for ISP.

Now about bootloader. If we talk about firmware bootloader (factory programmed) then it is not possible to re-program it for AT89C51RD2 because its bootloader is placed into ROM (this derivative has 64kb of user flash + 2kb of bootloader ROM).
As for T89C51RD2 then the firmware bootloader is placed in upper 1kb of flash memory (as result, you have 63kb of user flash + 1kb of bootloader flash). During Full Chip Erase bootloader may be erased (there is special bit which may prevent it if needs). If bootloader was erased then you may re-program it back ONLY with parallel programmer. The last version of bootloader may be download from Atmel site.

Regards,
Oleg