Hi, In addition to what Stefan described about ME descriptors, there is also BIOS CNTL register, that if BIOS enables it, you will not be able to write to flash using flashrom.
Refer to: Intel® C600 Series Chipset and Intel® X79 Express Chipset BIOS_CNTL—BIOS Control Register (LPC I/F—D31:F0) --- Rich On Tue, Aug 12, 2014 at 3:07 PM, Stefan Tauner < [email protected]> wrote: > On Tue, 12 Aug 2014 12:15:53 -0400 (EDT) > [email protected] wrote: > > > 0x54: 0x000f0000 FREG0: Warning: Flash Descriptor region > (0x00000000-0x0000ffff) is read-only. > > 0x58: 0x07ff0200 FREG1: BIOS region (0x00200000-0x007fffff) is > read-write. > > Hello Wen, > > it seems like this bogus kind of descriptor layout becomes popular. Let > me explain in case you don't understand: The descriptor region in the > first 4kB of the flash chip - similar to a partition table - defines > (among other things) which parts of the flash chip are used for what > components. Usually all addresses of the flas chip are covered by this > but sometimes vendor forget to do this properly - or do have no use for > it. > > The problem (for flashrom) is that the Intel SPI controllers forbid > accesses to addresses that are not covered by the descriptor regions - > like 0x00010000 to 0x001FFFFF in this case, which is almost a quarter > of the flash chip - but flashrom tries to read the whole chip > nevertheless (for good reasons). > > So flashrom works more or less as expected on that board as far as you > have tested it. That result is probably not very useful to you, but > fine with me for now... :) > > If you want to be able to write to the BIOS region, you > will also need my layout patches (they are also on github), and also > set the read_all_first variable in doit() in flashrom.c to 0. > I'd welcome such further tests of course but please be prepared for > recovery if need be. > > I have included Marc from Sage because I guess he may be able to tell > us about the reason for this. > -- > Kind regards/Mit freundlichen Grüßen, Stefan Tauner > > _______________________________________________ > flashrom mailing list > [email protected] > http://www.flashrom.org/mailman/listinfo/flashrom CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina Corporation (or any of its subsidiaries), or any other person or entity.
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