Difference between revisions of "Nvramtool"

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m (Lxbios moved to Nvramtool: lxbios was renamed to nvramtool.)
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'''lxbios''' is a utility for reading/writing coreboot parameters and displaying information from the coreboot table in CMOS.
+
'''nvramtool''' (previously known as '''lxbios''') is a utility for reading/writing coreboot parameters and displaying information from the coreboot table in CMOS.
  
 
The program works only on x86-based Linux systems that use coreboot.
 
The program works only on x86-based Linux systems that use coreboot.
Line 5: Line 5:
 
It can be downloaded via Subversion:
 
It can be downloaded via Subversion:
  
  svn co svn://coreboot.org/repos/trunk/util/lxbios
+
  svn co svn://coreboot.org/repos/trunk/util/nvramtool
  
== Using lxbios ==
+
== Using nvramtool ==
  
Running lxbios on a system running coreboot would yield a result like this:
+
Running nvramtool on a system running coreboot would yield a result like this:
  
   # ./lxbios -a
+
   # ./nvramtool -a
 
   boot_option = Fallback
 
   boot_option = Fallback
 
   last_boot = Fallback
 
   last_boot = Fallback
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# coreboot will ignore the CMOS table if the checksum is incorrect, and will fallback to its hardcoded defaults.
 
# coreboot will ignore the CMOS table if the checksum is incorrect, and will fallback to its hardcoded defaults.
# coreboot does not initialize the CMOS/NVRAM to default values. In other words, until you set values with the lxbios tool, your CMOS table will have an incorrect checksum, and will simply be ignored.
+
# coreboot does not initialize the CMOS/NVRAM to default values. In other words, until you set values with nvramtool, your CMOS table will have an incorrect checksum, and will simply be ignored.
# Not all of the fields that lxbios can set are used by coreboot on every mainboard.
+
# Not all of the fields that nvramtool can set are used by coreboot on every mainboard.
 
# Some of the fields are used by [[payloads]] - for instance all the fields that start with 'boot_' in the list above. [[FILO]] does not use those fields currently, but [[Etherboot]] does (someone confirm this please!).
 
# Some of the fields are used by [[payloads]] - for instance all the fields that start with 'boot_' in the list above. [[FILO]] does not use those fields currently, but [[Etherboot]] does (someone confirm this please!).
  
 
== Old websites ==
 
== Old websites ==
  
The lxbios tool is now maintained by the coreboot developers and this page is the main website of lxbios. For reference, the following websites were previously used, but are now deprecated:
+
The nvramtool tool is now maintained by the coreboot developers and this page is the main website of nvramtool. For reference, the following websites were previously used, but are now deprecated:
  
 
* http://www.llnl.gov/linux/lxbios/lxbios.html (dead)
 
* http://www.llnl.gov/linux/lxbios/lxbios.html (dead)

Revision as of 19:38, 1 March 2008

nvramtool (previously known as lxbios) is a utility for reading/writing coreboot parameters and displaying information from the coreboot table in CMOS.

The program works only on x86-based Linux systems that use coreboot.

It can be downloaded via Subversion:

svn co svn://coreboot.org/repos/trunk/util/nvramtool

Using nvramtool

Running nvramtool on a system running coreboot would yield a result like this:

 # ./nvramtool -a
 boot_option = Fallback
 last_boot = Fallback
 ECC_memory = Disable
 baud_rate = 115200
 hw_scrubber = Enable
 interleave_chip_selects = Enable
 max_mem_clock = 100Mhz
 dual_core = Enable
 power_on_after_fail = Enable
 debug_level = Spew
 boot_first = HDD
 boot_second = Network
 boot_third = Floppy
 boot_index = 0xe
 boot_countdown = 0xfa
 slow_cpu = off
 nmi = Enable
 iommu = Enable
 lxbios: Can not read coreboot parameter user_data because layout info specifies CMOS area that is too wide.

Things to know

  1. coreboot will ignore the CMOS table if the checksum is incorrect, and will fallback to its hardcoded defaults.
  2. coreboot does not initialize the CMOS/NVRAM to default values. In other words, until you set values with nvramtool, your CMOS table will have an incorrect checksum, and will simply be ignored.
  3. Not all of the fields that nvramtool can set are used by coreboot on every mainboard.
  4. Some of the fields are used by payloads - for instance all the fields that start with 'boot_' in the list above. FILO does not use those fields currently, but Etherboot does (someone confirm this please!).

Old websites

The nvramtool tool is now maintained by the coreboot developers and this page is the main website of nvramtool. For reference, the following websites were previously used, but are now deprecated:

GNU head This work is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or any later version. This work is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.