payloads/external/SeaBIOS: Allow setting buffers below 0xC0000

Add the option to coreboot to set the SeaBIOS buffers below 0xC0000.
This is a requirement on the Intel Rangeley processor
because it is designed so that only the processor can write
the higher memory areas.  This prevents USB and SATA from bus-mastering
into the buffers when they're set in the typical 0xE0000 area.

This will be set to Y unless defaulted to N by the mainboard or

Push the SeaBIOS buffers down to 0x90000 segment for Mohon Peak

Change-Id: I15638605d1c66a2277d4b852796db89978551a34
Signed-off-by: Martin Roth <>
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <>
Reviewed-by: Edward O'Callaghan <>
4 files changed