[flashrom] BIOS update using flashrom on an UEFI system

Lakesh_Sharma at DELL.com Lakesh_Sharma at DELL.com
Mon Feb 22 00:12:57 CET 2016

layout file option is being explored by our team.

From: David Hendricks [dhendrix at google.com]
Sent: Thursday, February 18, 2016 2:57 PM
To: Sharma, Lakesh
Cc: flashrom
Subject: Re: [flashrom] BIOS update using flashrom on an UEFI system

Hi Lakesh,
Did you ever find a solution for this? Probably the quickest solution is to figure out where the config data resides and write to the regions around it using a layout file.

It's an interesting problem that I suspect we'll see more often in the future, not just with UEFI. Storage of config data on the firmware ROM is becoming more common, and the firmware update utility of choice needs to become more aware of what portions of the ROM are safe to overwrite.

For ChromeOS platforms, we added a blob that maps the ROM content (flashmap, or fmap for short) so that our update scripts know which regions of the ROM to target when updating.

I'm not sure what the best way to do this for other systems, though. AFAIK this is all vendor-specific.

On Tue, Feb 9, 2016 at 6:21 PM, <Lakesh_Sharma at dell.com<mailto:Lakesh_Sharma at dell.com>> wrote:

In an UEFI based system (x86_64, Rangeley cpu), the bios bootup option
shows each UEFI partition. Where as in legacy bios mode, the bios bootup menu
would show just SSD, USB etc.
In case of UEFI system, the boot-order, boot-current etc (i.e. UEFI config data) is stored
in bios area ?

When we update bios using flashrom, we are seeing that the UEFI config data is getting lost/over-written.
Because of which, bios does not know that it is running on uefi system and probably tries to invoke
grub using legacy way, which hangs.

How can we instruct flashrom to not over-write UEFI config data in bios area.


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David Hendricks (dhendrix)
Systems Software Engineer, Google Inc.

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