How to unlock BIOS SPI flash after booting to Linux

[bsalha]

We would like to have write access to the BIOS SPI flash via the SPI flash controller inside the processor (Intel D1519) to provision a section of flash to encode serial number and other per-board nonvolatile fields. We are using the spi-intel Linux kernel module and we can read, but cannot write. We have provided the spi_intel.writeable=1 argument, but it turns out that the FLOCKDN bit is set, and the BIOS apparently does not list enabling write access as one of the available options in OPMENU.

We know this is possible because on another platform which has the same BIOS and CPU, but different kernel, we are able to write to the SPI flash via a modified flashrom binary (the modifications are closed source so we cannot look around unfortunately).

Does anyone know how to write to the SPI flash after booting to Linux?

[CarlosAM_INTEL]

Hello,  @bsalha: 

Thank you for contacting Intel Embedded Community.

The Intel® Pentium® Processor D1519  is a Broadwell-DE processor, as you may confirm in the following website:

https://www.intel.com/content/www/us/en/products/sku/91559/intel-pentium-processor-d1519-6m-cache-1-50-ghz/specifications.html 

We need to clarify that the Broadwell-DE processors have been discontinued and are no longer supported, as you may verify on the following website:

https://www.intel.com/content/www/us/en/support/articles/000022396/processors.html 

However, you may find the available documentation for the Broadwell-DE processors on the following website:

https://www.intel.com/content/www/us/en/products/platforms/details/broadwell-de/docs.html

Best regards,
@CarlosAM_INTEL.