Normally, at the powerup rpbase should be set to the default values, so no programming is required.
Yes, this is true if you are using the default SPI PRAM location.
Otherwise, the microcode patch downloading code is programming them correctly.
MPC852T skips the microcode patch does it not?
Are you sure you really need these? Could it be that you somehow hve overwritten the parameter area? What are the values in rpbase if you do not set them explicitly?
For the case where you intentionally want to move SPI to elsewhere (using ENET on SCC2), I will have to define CFG_SPI_DPMEM_OFFSET. since CFG_SPI_DPMEM_OFFSET is not assigned to spi->rpbase for MPC852T ( microcode patch is skipped), SPI is not relocated using your patch.
In my case I tested relocating SPI to 0x1800.
You can try that on your MPC852T.
Regards, David