Hello - The SPI controller only decodes the memory address for the BIOS region in SPI and so only the BIOS region is memory mapped. PDR needs to be access only through SPI commands. An option to consider is to make the BIOS region bigger to accommodate the contents intended for PDR and make it memory mapped. The advantage PDR provides is that its access permission can be set differently from the BIOS region. For example, PDR can be made writeable during run time even when the BIOS region is write protected. Thanks Ravi From: Sbl-devel [mailto:sbl-devel-bounces@lists.01.org] On Behalf Of Kruno Peric Sent: Friday, April 12, 2019 12:40 PM To: sbl-devel(a)lists.01.org Subject: [Sbl-devel] PDR partition DMA Is there a way to map the PDR boot partition to host cpu memory space? The goal is to read the SPI flash contents in the PDR region using DMA instead of register access. Thanks.