Editing GNU GRUB (section)

==={{Anchor|TRUSTED}}Variants===
GNU GRUB is [[free software]], so several variants have been created. Some notable ones, which have not been merged into GRUB mainline:
* [[OpenSolaris]] includes a modified GRUB Legacy that supports Solaris VTOC slices, automatic 64-bit kernel selection, and booting from [[ZFS]] (with [[Data compression|compression]] and multiple boot environments).<ref>[http://dlc.sun.com/osol/docs/content/SYSADV1/getov.html#fwbqs x86: Modifying Boot Behavior by Editing the GRUB Menu at Boot Time] {{webarchive|url=https://web.archive.org/web/20110719115732/http://dlc.sun.com/osol/docs/content/SYSADV1/getov.html |date=July 19, 2011}}, Modifying Solaris Boot Behavior on x86 Based Systems (Task Map) – System Administration Guide: Basic Administration</ref><ref>[http://docs.sun.com/app/docs/doc/819-2379/getnk?a=view x86: Supported GRUB Implementations] {{webarchive|url=https://web.archive.org/web/20091021160244/http://docs.sun.com/app/docs/doc/819-2379/getnk?a=view |date=October 21, 2009}}, (System Administration Guide: Basic Administration) – Sun Microsystems</ref>
* [[Google Summer of Code]] 2008 had a project to support GRUB legacy to boot from [[ext4]] formatted partitions.<ref>{{cite web
 | last      = Peng
 | first      = Tao
 | title      = Grub4ext4
 | url      = https://code.google.com/archive/p/grub4ext4/
 | access-date      = June 13, 2017
 | archive-date      = December 31, 2016
 | archive-url      = https://web.archive.org/web/20161231162436/https://code.google.com/archive/p/grub4ext4/
 | url-status      = live
 }}</ref>
* The [[Syllable Desktop|Syllable]] project made a modified version of GRUB to load the system from its [[AtheOS File System]].<ref>[http://web.syllable.org/documentation/FAQ.html#2_3 2.3 Why does Syllable have its own version of GRUB?] {{webarchive|url=https://web.archive.org/web/20110107003333/http://web.syllable.org/documentation/FAQ.html |date=January 7, 2011}}, Syllable Documentation</ref>
* ''TrustedGRUB'' extends GRUB by implementing verification of the system integrity and boot process security, using the [[Trusted Platform Module]] (TPM).<ref>{{cite web
 | url        = http://sourceforge.net/projects/trustedgrub/
 | title        = TrustedGRUB project
 | access-date        = November 18, 2014
 | website        = sourceforge.net
 | date = June 5, 2013
 | archive-date        = November 29, 2014
 | archive-url        = https://web.archive.org/web/20141129024847/http://sourceforge.net/projects/trustedgrub/
 | url-status        = live
 }}</ref>
* The Intel BIOS Implementation Test Suite (BITS) provides a GRUB environment for testing BIOSes and in particular their initialization of Intel processors, hardware, and technologies. BITS supports scripting via Python, and includes Python APIs to access various low-level functionality of the hardware platform, including ACPI, CPU and chipset registers, PCI, and PCI Express.<ref>[https://biosbits.org: BIOS Implementation Test Suite] {{Webarchive|url=https://web.archive.org/web/20161019132535/https://biosbits.org/ |date=October 19, 2016 }}, Official BITS website</ref>
* GRUB4DOS is a GRUB legacy fork that improves the installation experience on DOS and [[Microsoft Windows]] by putting everything besides the GRLDR config in one image file. It can be loaded directly from DOS, or by [[NTLDR]] or [[Windows Boot Manager]].<ref>{{cite web |title=grub4dos |url=https://sites.google.com/site/grubdos/ |website=Google Site |access-date=7 April 2019 |archive-date=April 7, 2019 |archive-url=https://web.archive.org/web/20190407043143/https://sites.google.com/site/grubdos/ |url-status=live }}</ref><ref>{{cite web |title=GRUB for DOS Introduction |url=http://grub4dos.sourceforge.net/wiki/index.php/Grub4dos_tutorial |website=grub4dos.sourceforge.net |access-date=7 April 2019 |archive-url=https://web.archive.org/web/20190407042958/http://microsaint.narod.ru/_Info_Grub4Dos/Grub4dos_tutorial.html |archive-date=7 April 2019 |date=2007}}</ref> GRUB4DOS is under active development and as of 2021 supports UEFI.<ref>{{GitHub|https://github.com/chenall/grub4dos}}</ref>