Fallback mechanism

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Revision as of 11:56, 21 February 2013 by PatrickGeorgi (talk | contribs) (PatrickGeorgi moved page Fallback mecanism to Fallback mechanism: typo in page name)

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The fallback mecanism permits to have 2 different romstage,ramstage,payload in the same images under a different prefix. The switch between both can be governed by an nvram configuration parameter.


  • build the coreboot image as usual, it will produce an image in build/coreboot.rom
  • After the first build run:
make menuconfig
  • Optionally change the payload.
  • Go in
General setup  --->
  • Change:
(fallback) CBFS prefix to use


(normal) CBFS prefix to use
  • Go back to the main menu and select:
Architecture (x86)  --->

select the following option:

[*] Update existing coreboot.rom image

Exit and save and rebuild...

The image will then have fallback and normal:

Name                           Offset     Type         Size
cmos_layout.bin                0x0        cmos_layout  1776
pci1002,9710.rom               0x740      optionrom    60928
fallback/romstage              0xf580     stage        92823
fallback/coreboot_ram          0x26080    stage        66639
fallback/payload               0x36540    payload      54976
config                         0x43c40    raw          4455
normal/romstage                0x44e00    stage        92823
normal/coreboot_ram            0x5b8c0    stage        68820
normal/payload                 0x6c600    payload      159949
(empty)                        0x93700    null         442136