I am using sc1200 that can address upto 4GB physical address). My flash memory is 32Mbit. Generally the ROM chip is mapped in hardware to the high physical address (0xFFFFFFFF - 0xFFC00000). My SDRAM is 32MByte. It is mapped in hardware to CPU address (0x00000000 - 1FFFFFF). My Bios program is kept in the flash memory. After the hardware initialization is done and before going with the int 19h interrupt, my bios program scans for option Rom from location 0xC8000h. So when it starts scanning from location 0xC8000, is any hardware remapping that has to be done.